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All questions of Practice Model Test Papers for Class 6 Exam
Select the correct pair:- a) Vitamin B1 - Beriberi
- b) Vitamin A - Rickets
- c) Vitamin C - Goiter
- d) Vitamin D - Anaemia
Correct answer is option 'A'. Can you explain this answer?
Select the correct pair:
a)
Vitamin B1 - Beriberi
b)
Vitamin A - Rickets
c)
Vitamin C - Goiter
d)
Vitamin D - Anaemia
|
Aman Choudhury answered |
Vitamins and Their Deficiency Diseases
Vitamins are essential nutrients required by our body in small amounts for various physiological functions. A lack of vitamins in our diet leads to various deficiency diseases. Let's understand the correct pair of vitamins and their deficiency diseases.
Correct Pair
Vitamin B1 - Beriberi
Thiamine or Vitamin B1 is essential for the proper functioning of the nervous system, muscles, and heart. It helps in the breakdown of carbohydrates and provides energy to the body. A deficiency of Vitamin B1 leads to a disease called Beriberi. Beriberi is a neurological and cardiovascular disorder that affects the nervous system and the heart. It is characterized by muscle weakness, loss of sensation in hands and feet, and heart failure.
Incorrect Pairs
b)Vitamin A - Rickets
Vitamin A is essential for maintaining healthy eyesight, skin, and immune system. It is not related to Rickets. Rickets is a deficiency disease of Vitamin D. Vitamin D is important for the absorption of calcium and phosphorus in the body. A deficiency of Vitamin D leads to Rickets, which is characterized by weak and soft bones, bowed legs, and stunted growth.
c)Vitamin C - Goiter
Vitamin C or Ascorbic acid is important for the growth and repair of tissues in the body. It also helps in the absorption of iron and boosts the immune system. It is not related to Goiter. Goiter is a condition where the thyroid gland in the neck becomes enlarged due to the deficiency of iodine. Iodine is required for the synthesis of thyroid hormones.
d)Vitamin D - Anaemia
Vitamin D is important for the absorption of calcium and phosphorus in the body. It is not related to Anaemia. Anaemia is a condition where there is a deficiency of red blood cells or haemoglobin in the blood. Iron and Vitamin B12 are important for the production of red blood cells. A deficiency of these nutrients leads to Anaemia.
Conclusion
Hence, the correct pair of vitamins and their deficiency disease is Vitamin B1 - Beriberi. It is important to include a balanced diet with all the essential vitamins and minerals to prevent any deficiency disease.
Vitamins are essential nutrients required by our body in small amounts for various physiological functions. A lack of vitamins in our diet leads to various deficiency diseases. Let's understand the correct pair of vitamins and their deficiency diseases.
Correct Pair
Vitamin B1 - Beriberi
Thiamine or Vitamin B1 is essential for the proper functioning of the nervous system, muscles, and heart. It helps in the breakdown of carbohydrates and provides energy to the body. A deficiency of Vitamin B1 leads to a disease called Beriberi. Beriberi is a neurological and cardiovascular disorder that affects the nervous system and the heart. It is characterized by muscle weakness, loss of sensation in hands and feet, and heart failure.
Incorrect Pairs
b)Vitamin A - Rickets
Vitamin A is essential for maintaining healthy eyesight, skin, and immune system. It is not related to Rickets. Rickets is a deficiency disease of Vitamin D. Vitamin D is important for the absorption of calcium and phosphorus in the body. A deficiency of Vitamin D leads to Rickets, which is characterized by weak and soft bones, bowed legs, and stunted growth.
c)Vitamin C - Goiter
Vitamin C or Ascorbic acid is important for the growth and repair of tissues in the body. It also helps in the absorption of iron and boosts the immune system. It is not related to Goiter. Goiter is a condition where the thyroid gland in the neck becomes enlarged due to the deficiency of iodine. Iodine is required for the synthesis of thyroid hormones.
d)Vitamin D - Anaemia
Vitamin D is important for the absorption of calcium and phosphorus in the body. It is not related to Anaemia. Anaemia is a condition where there is a deficiency of red blood cells or haemoglobin in the blood. Iron and Vitamin B12 are important for the production of red blood cells. A deficiency of these nutrients leads to Anaemia.
Conclusion
Hence, the correct pair of vitamins and their deficiency disease is Vitamin B1 - Beriberi. It is important to include a balanced diet with all the essential vitamins and minerals to prevent any deficiency disease.
Which of the following is not a form of precipitation?- a)Snow
- b)Rain
- c)Hailstone
- d)None of them
Correct answer is option 'D'. Can you explain this answer?
Which of the following is not a form of precipitation?
a)
Snow
b)
Rain
c)
Hailstone
d)
None of them
|
Arjun Yadav answered |
The correct answer is option 'D' - None of them.
Precipitation refers to any form of water that falls from the atmosphere and reaches the Earth's surface. It includes various forms such as rain, snow, sleet, and hail. Let's discuss each of these forms of precipitation to understand why option 'D' is the correct answer.
1. **Rain**: Rain is the most common form of precipitation. It occurs when water droplets in clouds combine and become heavy enough to fall to the ground. Raindrops can vary in size from small drizzles to heavy downpours.
2. **Snow**: Snow is another form of precipitation that occurs when the temperature in the atmosphere is below freezing point. Water vapor in the clouds freezes into ice crystals, which then come together to form snowflakes. Snowflakes are unique in shape and can accumulate on the ground, creating a layer of snow.
3. **Hailstone**: Hailstones are balls or irregular lumps of ice that form in severe thunderstorms. They are different from other forms of precipitation as they are solid rather than liquid. Hailstones are formed when there are strong updrafts in the storm clouds, causing raindrops to be carried upwards into extremely cold regions of the cloud. The raindrops freeze into ice pellets, and as they are carried up and down by strong air currents, additional layers of ice are added, making the hailstone grow larger. Eventually, the hailstones become too heavy for the updrafts to support, and they fall to the ground.
Now, considering the options given, all of them - snow, rain, and hailstone - are forms of precipitation. Therefore, the correct answer is option 'D' - None of them.
Precipitation refers to any form of water that falls from the atmosphere and reaches the Earth's surface. It includes various forms such as rain, snow, sleet, and hail. Let's discuss each of these forms of precipitation to understand why option 'D' is the correct answer.
1. **Rain**: Rain is the most common form of precipitation. It occurs when water droplets in clouds combine and become heavy enough to fall to the ground. Raindrops can vary in size from small drizzles to heavy downpours.
2. **Snow**: Snow is another form of precipitation that occurs when the temperature in the atmosphere is below freezing point. Water vapor in the clouds freezes into ice crystals, which then come together to form snowflakes. Snowflakes are unique in shape and can accumulate on the ground, creating a layer of snow.
3. **Hailstone**: Hailstones are balls or irregular lumps of ice that form in severe thunderstorms. They are different from other forms of precipitation as they are solid rather than liquid. Hailstones are formed when there are strong updrafts in the storm clouds, causing raindrops to be carried upwards into extremely cold regions of the cloud. The raindrops freeze into ice pellets, and as they are carried up and down by strong air currents, additional layers of ice are added, making the hailstone grow larger. Eventually, the hailstones become too heavy for the updrafts to support, and they fall to the ground.
Now, considering the options given, all of them - snow, rain, and hailstone - are forms of precipitation. Therefore, the correct answer is option 'D' - None of them.
Select the option the letters of which, on reshuffling, will give the term given to describe water seepage into the ground.- a)Ntciepirtaipo
- b)Atooniaervp
- c)Aitfinlronit
- d)Tspratniaoinr
Correct answer is option 'C'. Can you explain this answer?
Select the option the letters of which, on reshuffling, will give the term given to describe water seepage into the ground.
a)
Ntciepirtaipo
b)
Atooniaervp
c)
Aitfinlronit
d)
Tspratniaoinr
|
Shubham Chakraborty answered |
Infiltration is the process by which water on the ground surface enters the soil. It is commonly used in both hydrology and soil sciences. The infiltration capacity is defined as the maximum rate of infiltration.
Which of the following actions will help in reducing pollution?
1. Restricting smoking in public areas
2. Treatment of sewage to remove human waste
3. Using unleaded petrol in cars
4. Spraying pesticides on paints to kill pests- a)1, 2 and 4
- b)1, 2 and 3
- c)1 and 2
- d)1 and 4
Correct answer is option 'B'. Can you explain this answer?
Which of the following actions will help in reducing pollution?
1. Restricting smoking in public areas
2. Treatment of sewage to remove human waste
3. Using unleaded petrol in cars
4. Spraying pesticides on paints to kill pests
1. Restricting smoking in public areas
2. Treatment of sewage to remove human waste
3. Using unleaded petrol in cars
4. Spraying pesticides on paints to kill pests
a)
1, 2 and 4
b)
1, 2 and 3
c)
1 and 2
d)
1 and 4
|
Coachify answered |
Option 'B' is correct.
Cooking of rice is an example of:- a)Reversible change
- b)Irreversible change
- c)Irreversible and endothermic change
- d)Reversible and endothermic change
Correct answer is option 'C'. Can you explain this answer?
Cooking of rice is an example of:
a)
Reversible change
b)
Irreversible change
c)
Irreversible and endothermic change
d)
Reversible and endothermic change
|
Get Idea answered |
- Cooking rice is an example of an irreversible and endothermic change.
- This means that when rice is cooked, it undergoes a transformation that cannot be reversed.
- During this process, rice absorbs heat and moisture, leading to physical and chemical changes that alter its structure and properties.
Which of the following statements should be followed while using a symbol for a unit of a physical quantity?- a)They can be written in full
- b)The symbol named after scientist should have capital letter
- c)They take plural forms
- d)They should always be written in lowercase
Correct answer is option 'B'. Can you explain this answer?
Which of the following statements should be followed while using a symbol for a unit of a physical quantity?
a)
They can be written in full
b)
The symbol named after scientist should have capital letter
c)
They take plural forms
d)
They should always be written in lowercase
|
|
Abhishek Phogat answered |
E.g ~ N/m^2 and Hz.... Both Newton and Hertz are scientists.. Hence written in capitals...
Read the features of a plant as given below.
1. Roots are much shorter in size.
2. Stems are generally long and narrow.
3. Stems possess air spaces.
4. They have waxy upper surface.
Q. To which of these habitats does this plant belong?
- a)Desert
- b)Polar region
- c)Tropical region
- d)Aquatic
Correct answer is option 'D'. Can you explain this answer?
Read the features of a plant as given below.
1. Roots are much shorter in size.
2. Stems are generally long and narrow.
3. Stems possess air spaces.
4. They have waxy upper surface.
1. Roots are much shorter in size.
2. Stems are generally long and narrow.
3. Stems possess air spaces.
4. They have waxy upper surface.
Q. To which of these habitats does this plant belong?
a)
Desert
b)
Polar region
c)
Tropical region
d)
Aquatic
|
|
Bhumika Mamar answered |
Desert is the correct answer
This set of elements produce strong magnets?- a)Steel and aluminum only
- b)Steel and nickle only
- c)Steel and pure iron only
- d)Pure iron, steel and an alloy of Al, Co, Ni and Fe
Correct answer is option 'D'. Can you explain this answer?
This set of elements produce strong magnets?
a)
Steel and aluminum only
b)
Steel and nickle only
c)
Steel and pure iron only
d)
Pure iron, steel and an alloy of Al, Co, Ni and Fe
|
Gayatri Chavan answered |
The correct answer is option "d".
Pure iron, steel, and an alloy of aluminum, cobalt, nickel, and iron (also known as "Alnico") are all materials that are known to produce strong magnets. Iron and steel are magnetic materials that are commonly used in the production of magnets, and the addition of cobalt, nickel, and aluminum to iron can further enhance its magnetic properties. These materials are often used in the production of permanent magnets, which are magnets that retain their magnetism over time.
Light is a form of energy produced by a- a)Luminous object
- b)Transparent object
- c)Non-luminous object
- d)Opaque object
Correct answer is option 'A'. Can you explain this answer?
Light is a form of energy produced by a
a)
Luminous object
b)
Transparent object
c)
Non-luminous object
d)
Opaque object
|
|
Coachify answered |
Light is a form of energy produced by a luminous object. An object is considered luminous if it emits its own light.
A solid, transparent sphere has a small, opaque center. When observed from outside, the apparent position of the dot will be:- a)Farther away from the eye than its actual position
- b)Closer to the eye than its actual position
- c)The same as its actual position
- d)None of these
Correct answer is option 'C'. Can you explain this answer?
A solid, transparent sphere has a small, opaque center. When observed from outside, the apparent position of the dot will be:
a)
Farther away from the eye than its actual position
b)
Closer to the eye than its actual position
c)
The same as its actual position
d)
None of these
|
|
Meena Yadav answered |
The correct option is 'C'
The same as its actual position.
The same as its actual position.
Piyush does not consume protein-rich food for a long time. Which of the following disorders can he face?- a)Poor vision
- b)Swelling of face
- c)Weak teeth
- d)
Bleeding gums
Correct answer is option 'B'. Can you explain this answer?
Piyush does not consume protein-rich food for a long time. Which of the following disorders can he face?
a)
Poor vision
b)
Swelling of face
c)
Weak teeth
d)
Bleeding gums
|
Gunjan Lakhani answered |
Deficiency of proteins in the diet for a long time results in swelling of the face, swollen neck, undergrowth of the body, etc. This is because proteins are the building blocks of the body and should be taken in sufficient amounts.
A young plant is seen to grow from the underground stem as shown below.
Q. The young plant gets its food from_____________ .- a)Its roots
- b)Its seeds
- c)The buds of the underground stem
- d)The food stored in the underground stem
Correct answer is option 'D'. Can you explain this answer?
A young plant is seen to grow from the underground stem as shown below.
Q. The young plant gets its food from_____________ .
a)
Its roots
b)
Its seeds
c)
The buds of the underground stem
d)
The food stored in the underground stem
|
|
Meena Yadav answered |
The foods stored in underground stem.
At 8 a.m., the shadow of Ananya’s flat was as shown below.
Q. Which one of the following diagrams shows the shadow of her flat at 6.30 p.m.?
- a)
- b)
- c)
- d)None of these
Correct answer is option 'A'. Can you explain this answer?
At 8 a.m., the shadow of Ananya’s flat was as shown below.
Q. Which one of the following diagrams shows the shadow of her flat at 6.30 p.m.?
a)
b)
c)
d)
None of these
|
|
Naksh Manhas answered |
Because sun sets in west and the will be in East
The needle of the compass is made of a magnet because it .- a)Attracts metal
- b)Comes to rest in a north-south direction
- c)Gets deflected when a magnet is brought closer
- d)B and Cboth
Correct answer is option 'D'. Can you explain this answer?
The needle of the compass is made of a magnet because it .
a)
Attracts metal
b)
Comes to rest in a north-south direction
c)
Gets deflected when a magnet is brought closer
d)
B and Cboth
|
Varun Patel answered |
Introduction:
The needle of a compass is made of a magnet because it exhibits certain properties that make it ideal for use in a compass. The magnetized needle aligns itself with the Earth's magnetic field, allowing it to point in a north-south direction. Additionally, the needle also gets deflected when a magnet is brought closer, demonstrating its magnetic properties.
Attracts metal:
One of the properties of a magnet is its ability to attract certain types of metals, such as iron and steel. This attraction is due to the magnetic field produced by the magnet. When a metal object comes into contact with the magnet, it experiences a force of attraction and may be pulled towards it. The needle of a compass, being made of a magnet, also possesses this property. This is why the needle can attract metal objects, such as paperclips, when brought close to them.
Comes to rest in a north-south direction:
The Earth has its own magnetic field, with magnetic north and south poles. The needle of a compass is magnetized, which means it has its own north and south poles as well. When the compass is held horizontally, the needle aligns itself with the Earth's magnetic field. The north pole of the needle is attracted towards the Earth's magnetic south pole, while the south pole of the needle is attracted towards the Earth's magnetic north pole. As a result, the needle comes to rest in a north-south direction, allowing us to determine the cardinal directions.
Gets deflected when a magnet is brought closer:
When a magnet is brought near another magnet, it can exert a force on it. This force can cause the magnet to move or get deflected from its original position. In the case of a compass needle, which is also a magnet, it exhibits the same behavior. When a magnet is brought close to the compass needle, the needle can get deflected from its north-south alignment and point towards the nearby magnet instead. This deflection occurs due to the interaction between the magnetic fields of the two magnets.
Conclusion:
The needle of a compass is made of a magnet because it possesses certain properties that make it suitable for use in a compass. It can attract metal objects, comes to rest in a north-south direction aligning with the Earth's magnetic field, and gets deflected when a magnet is brought closer. These properties allow the compass needle to accurately indicate the cardinal directions and make it a reliable tool for navigation.
The needle of a compass is made of a magnet because it exhibits certain properties that make it ideal for use in a compass. The magnetized needle aligns itself with the Earth's magnetic field, allowing it to point in a north-south direction. Additionally, the needle also gets deflected when a magnet is brought closer, demonstrating its magnetic properties.
Attracts metal:
One of the properties of a magnet is its ability to attract certain types of metals, such as iron and steel. This attraction is due to the magnetic field produced by the magnet. When a metal object comes into contact with the magnet, it experiences a force of attraction and may be pulled towards it. The needle of a compass, being made of a magnet, also possesses this property. This is why the needle can attract metal objects, such as paperclips, when brought close to them.
Comes to rest in a north-south direction:
The Earth has its own magnetic field, with magnetic north and south poles. The needle of a compass is magnetized, which means it has its own north and south poles as well. When the compass is held horizontally, the needle aligns itself with the Earth's magnetic field. The north pole of the needle is attracted towards the Earth's magnetic south pole, while the south pole of the needle is attracted towards the Earth's magnetic north pole. As a result, the needle comes to rest in a north-south direction, allowing us to determine the cardinal directions.
Gets deflected when a magnet is brought closer:
When a magnet is brought near another magnet, it can exert a force on it. This force can cause the magnet to move or get deflected from its original position. In the case of a compass needle, which is also a magnet, it exhibits the same behavior. When a magnet is brought close to the compass needle, the needle can get deflected from its north-south alignment and point towards the nearby magnet instead. This deflection occurs due to the interaction between the magnetic fields of the two magnets.
Conclusion:
The needle of a compass is made of a magnet because it possesses certain properties that make it suitable for use in a compass. It can attract metal objects, comes to rest in a north-south direction aligning with the Earth's magnetic field, and gets deflected when a magnet is brought closer. These properties allow the compass needle to accurately indicate the cardinal directions and make it a reliable tool for navigation.
Which of the following substances is not soluble in water?- a)Copper sulphate
- b)Potassium permanganate
- c)Sugar
- d)All are soluble.
Correct answer is option 'D'. Can you explain this answer?
Which of the following substances is not soluble in water?
a)
Copper sulphate
b)
Potassium permanganate
c)
Sugar
d)
All are soluble.
|
Rohini Seth answered |
All of the given substances are soluble in water and are called solute. Solute is the substance which is dissolved in a solvent.
Study the circuit below.
The switches at points A, B, C, D and E were closed and all 3 electrical appliances were working.
Q. Opening the switch at point would allow both the TV and the lamp to work.- a)A
- b)B
- c)C
- d)E
Correct answer is option 'A'. Can you explain this answer?
Study the circuit below.
The switches at points A, B, C, D and E were closed and all 3 electrical appliances were working.
Q. Opening the switch at point would allow both the TV and the lamp to work.
Q. Opening the switch at point would allow both the TV and the lamp to work.
a)
A
b)
B
c)
C
d)
E
|
Atharva Tiwari answered |
Dhdof4irj
A is the father of B and C is the mother of D. M is the paternal uncle of D. If B and D are siblings, then how is M related to A?- a)Father
- b)Brother
- c)Uncle
- d)Son
Correct answer is option 'B'. Can you explain this answer?
A is the father of B and C is the mother of D. M is the paternal uncle of D. If B and D are siblings, then how is M related to A?
a)
Father
b)
Brother
c)
Uncle
d)
Son
|
Aditya Menon answered |
Family Relationships Explained
Understanding family relationships can sometimes be tricky. Let’s break down the information given in this problem to clarify how M is related to A.
Key Relationships
- A is the father of B: This indicates that A is the parent of B.
- C is the mother of D: C is a separate parent, indicating that D is not a child of A.
- M is the paternal uncle of D: This means that M is the brother of A (since a paternal uncle is the brother of one of the child's parents).
- B and D are siblings: This means that B and D share at least one parent. Since B is A's child, it follows that D must also be A's child. Therefore, A is also D's parent, making C D's mother.
Connecting the Dots
- Since D is the child of A and C, and M is identified as the paternal uncle of D, it confirms that M is the brother of A.
- This establishes that M is related to A as his sibling.
Conclusion
Thus, the relationship can be summarized as follows:
- M is A's brother.
Therefore, the correct answer is option 'B' (Brother).
Understanding family relationships can sometimes be tricky. Let’s break down the information given in this problem to clarify how M is related to A.
Key Relationships
- A is the father of B: This indicates that A is the parent of B.
- C is the mother of D: C is a separate parent, indicating that D is not a child of A.
- M is the paternal uncle of D: This means that M is the brother of A (since a paternal uncle is the brother of one of the child's parents).
- B and D are siblings: This means that B and D share at least one parent. Since B is A's child, it follows that D must also be A's child. Therefore, A is also D's parent, making C D's mother.
Connecting the Dots
- Since D is the child of A and C, and M is identified as the paternal uncle of D, it confirms that M is the brother of A.
- This establishes that M is related to A as his sibling.
Conclusion
Thus, the relationship can be summarized as follows:
- M is A's brother.
Therefore, the correct answer is option 'B' (Brother).
Find the odd one out in the given series.43, 88, 179, 358- a)43
- b)88
- c)179
- d)358
Correct answer is option 'C'. Can you explain this answer?
Find the odd one out in the given series.
43, 88, 179, 358
a)
43
b)
88
c)
179
d)
358
|
EduRev Class 6 answered |
Each time, we are multiplying by 2 and then adding 2. 43 x 2 = 86 + 2 = 88 88 x 2 = 176 = 176 + 2 = 178 (actual) 178 x 2 = 356 + 2 = 358 So, 179 is the odd one out..
Mary made the following statements about photosynthesis.Which of the statements is/are INCORRECT?- a)Oxygen production takes place during photosynthesis
- b)Only heat energy is needed for plants to carry out photosynthesis
- c)Photosynthesis can only take place in cells that contain chloroplasts
- d)During respiration, the excess food made during photosynthesis is used up for energy
Correct answer is option 'B'. Can you explain this answer?
Mary made the following statements about photosynthesis.Which of the statements is/are INCORRECT?
a)
Oxygen production takes place during photosynthesis
b)
Only heat energy is needed for plants to carry out photosynthesis
c)
Photosynthesis can only take place in cells that contain chloroplasts
d)
During respiration, the excess food made during photosynthesis is used up for energy
|
Manasing Pawar answered |
Only heat energy is needed for plants to carry out photosynthesis
Pulling out seed from cotton is called- a)Sieving
- b)Ginning
- c)Filtering
- d)Looming
Correct answer is option 'B'. Can you explain this answer?
Pulling out seed from cotton is called
a)
Sieving
b)
Ginning
c)
Filtering
d)
Looming
|
Subset Academy answered |
The process of separating out seeds from the cotton fibre is called ginning.
Decantation process is used to separate:- a)Two immiscible liquids
- b)Two miscible liquids
- c)Two metals in an alloy
- d)Solid-solid mixture
Correct answer is option 'A'. Can you explain this answer?
Decantation process is used to separate:
a)
Two immiscible liquids
b)
Two miscible liquids
c)
Two metals in an alloy
d)
Solid-solid mixture
|
|
Jyoti Kaur answered |
Decantation Process
Decantation is a process used to separate two immiscible liquids, i.e., liquids that do not mix together. This method is based on the principle that immiscible liquids have different densities, allowing them to separate naturally when left undisturbed.
Procedure
- The two immiscible liquids are allowed to settle in a container.
- Once settled, the heavier liquid (having higher density) settles at the bottom, while the lighter liquid (having lower density) forms a separate layer on top.
- The container is then tilted carefully, and the lighter liquid is poured out slowly without disturbing the heavier liquid layer. This process is known as decantation.
Example
For example, if a mixture of water and oil is left to stand, the oil, being less dense, will float on top of the water. By carefully pouring off the oil without disturbing the water layer beneath, the two liquids can be separated using decantation.
Significance
Decantation is a simple and effective method for separating immiscible liquids without the need for complex equipment or chemicals. It is commonly used in various industries such as food processing, pharmaceuticals, and wastewater treatment.
Decantation is a process used to separate two immiscible liquids, i.e., liquids that do not mix together. This method is based on the principle that immiscible liquids have different densities, allowing them to separate naturally when left undisturbed.
Procedure
- The two immiscible liquids are allowed to settle in a container.
- Once settled, the heavier liquid (having higher density) settles at the bottom, while the lighter liquid (having lower density) forms a separate layer on top.
- The container is then tilted carefully, and the lighter liquid is poured out slowly without disturbing the heavier liquid layer. This process is known as decantation.
Example
For example, if a mixture of water and oil is left to stand, the oil, being less dense, will float on top of the water. By carefully pouring off the oil without disturbing the water layer beneath, the two liquids can be separated using decantation.
Significance
Decantation is a simple and effective method for separating immiscible liquids without the need for complex equipment or chemicals. It is commonly used in various industries such as food processing, pharmaceuticals, and wastewater treatment.
When a piece of iron metal is placed in copper sulphate solution, which of the following is not observed?- a)Iron displaces copper from the sulphate solution.
- b)There is no change in colour of the solution.
- c)Iron acquires reddish-brown colour.
- d)All of the above
Correct answer is option 'B'. Can you explain this answer?
When a piece of iron metal is placed in copper sulphate solution, which of the following is not observed?
a)
Iron displaces copper from the sulphate solution.
b)
There is no change in colour of the solution.
c)
Iron acquires reddish-brown colour.
d)
All of the above
|
|
Rohini Seth answered |
Iron displaces copper from the sulphate solution leading to the formation of ferrous sulphate and copper.
CuSO4 + Fe → FeSO4 + Cu
The blue colour of the solution changes to pale green and there is a reddish-brown deposit of copper on the piece of iron.
This is a displacement reaction in which a more reactive metal displaces a less reactive metal from its salt solution.
The blue colour of the solution changes to pale green and there is a reddish-brown deposit of copper on the piece of iron.
This is a displacement reaction in which a more reactive metal displaces a less reactive metal from its salt solution.
When HCl present in the stomach is secreted in a large quantity, it causes troubles. What is the remedy for this?- a)Use of NaOH
- b)Use of Milk of Magnesia
- c)Use of water
- d)Use of pepsin
Correct answer is option 'B'. Can you explain this answer?
When HCl present in the stomach is secreted in a large quantity, it causes troubles. What is the remedy for this?
a)
Use of NaOH
b)
Use of Milk of Magnesia
c)
Use of water
d)
Use of pepsin
|
Praveen Kumar answered |
Magnesium hydroxide reduces stomach acid and increases water in the intestines which may induce defecation. Magnesium hydroxide is used as a laxative to relieve occasional constipation (irregularity) and as an antacid to relieve indigestion, sour stomach, and heartburn.
If the the refractive index of any glass is 1, then which of the following statements is true regarding the glass?- a)The refracted ray will turn towards normal after refraction.
- b)The refracted ray will turn away from normal after refraction.
- c)The light will be partially reflected.
- d)The glass will become invisible.
Correct answer is option 'D'. Can you explain this answer?
If the the refractive index of any glass is 1, then which of the following statements is true regarding the glass?
a)
The refracted ray will turn towards normal after refraction.
b)
The refracted ray will turn away from normal after refraction.
c)
The light will be partially reflected.
d)
The glass will become invisible.
|
|
Aaditya Chawla answered |
The Refractive Index of Glass
The refractive index (n) of a material describes how light behaves when it passes through it. For glass, a refractive index of 1 means that light travels through it at the same speed as in a vacuum.
Implications of n = 1
- No Refraction: When the refractive index is 1, light does not bend as it enters or exits the glass. This means:
- The angle of incidence equals the angle of refraction.
- Invisibility of Glass:
- Since light passes through without bending, the glass becomes virtually invisible. There is no distortion of light, making it hard for the human eye to perceive the boundaries of the glass.
Analysis of Other Options
- Option A: The refracted ray will turn towards the normal after refraction.
- False: With a refractive index of 1, light does not change direction.
- Option B: The refracted ray will turn away from the normal after refraction.
- False: Again, light travels straight without bending.
- Option C: The light will be partially reflected.
- False: No partial reflection occurs since there’s no change in speed or direction.
Conclusion
- Given the refractive index of 1, the correct statement is that the glass will become invisible. This unique property is significant in applications like optical fibers and lenses, where clarity and minimal light distortion are crucial.
The refractive index (n) of a material describes how light behaves when it passes through it. For glass, a refractive index of 1 means that light travels through it at the same speed as in a vacuum.
Implications of n = 1
- No Refraction: When the refractive index is 1, light does not bend as it enters or exits the glass. This means:
- The angle of incidence equals the angle of refraction.
- Invisibility of Glass:
- Since light passes through without bending, the glass becomes virtually invisible. There is no distortion of light, making it hard for the human eye to perceive the boundaries of the glass.
Analysis of Other Options
- Option A: The refracted ray will turn towards the normal after refraction.
- False: With a refractive index of 1, light does not change direction.
- Option B: The refracted ray will turn away from the normal after refraction.
- False: Again, light travels straight without bending.
- Option C: The light will be partially reflected.
- False: No partial reflection occurs since there’s no change in speed or direction.
Conclusion
- Given the refractive index of 1, the correct statement is that the glass will become invisible. This unique property is significant in applications like optical fibers and lenses, where clarity and minimal light distortion are crucial.
Which two signs should be interchanged to make the equation correct?6 + (9 - 3) ÷ (8 + 1) × (7 - 4) = 24- a)× and ÷
- b)+ and ÷
- c)- and ÷
- d)+ and -
Correct answer is option 'A'. Can you explain this answer?
Which two signs should be interchanged to make the equation correct?
6 + (9 - 3) ÷ (8 + 1) × (7 - 4) = 24
a)
× and ÷
b)
+ and ÷
c)
- and ÷
d)
+ and -
|
|
Gunjan Lakhani answered |
After interchanging × and ÷,
We get
6 + (9 - 3) × (8 + 1) ÷ (7 - 4) = 6 + 6 x 9 ÷ 3 = 24
We get
6 + (9 - 3) × (8 + 1) ÷ (7 - 4) = 6 + 6 x 9 ÷ 3 = 24
When the temperature of the solid is increased, the energy of the particles increases.- a)Heat
- b)Potential
- c)Kinetic
- d)Chemical
Correct answer is option 'C'. Can you explain this answer?
When the temperature of the solid is increased, the energy of the particles increases.
a)
Heat
b)
Potential
c)
Kinetic
d)
Chemical
|
|
Gayatri Chavan answered |
When the temperature of a solid is increased, the energy of its particles increases. This increase in energy is due to an increase in the kinetic energy of the particles. The kinetic energy of a particle is the energy it possesses due to its motion. When the temperature of a solid increases, the particles gain more kinetic energy and move faster.
Therefore, the correct answer is "Kinetic." Heat and potential energy are not directly related to the motion of particles in a solid. Chemical energy is the energy stored in the bonds between atoms or molecules, and it is not affected by changes in temperature.
Sameer’s torch does not light up. This could be because of the following reason:- a)There is a gap between the batteries
- b)The metal tip of the bulb is not connected to one of the batteries
- c)The positive terminal of one battery is not connected to the negative terminal of the next battery
- d)All are correct
Correct answer is option 'D'. Can you explain this answer?
Sameer’s torch does not light up. This could be because of the following reason:
a)
There is a gap between the batteries
b)
The metal tip of the bulb is not connected to one of the batteries
c)
The positive terminal of one battery is not connected to the negative terminal of the next battery
d)
All are correct
|
Saranya Chakraborty answered |
Sameer is a common Indian given name meaning "uniter" or "one who brings people together." It is often used as a first name for boys in India and other South Asian countries. Sameer can also be spelled as Samir or Samer.
Identify the fiber:
- a)Cotton
- b)Linen
- c)Jute
- d)Synthetic
Correct answer is option 'C'. Can you explain this answer?
Identify the fiber:
a)
Cotton
b)
Linen
c)
Jute
d)
Synthetic
|
|
Get Idea answered |
- The fiber in the image is Jute
- Jute is a long, soft, shiny vegetable fiber used for making rope and burlap.
In which of the following cases will regular reflection not take place when a beam of light strikes it?- a)Marble flooring with oil spread over
- b)Mirror
- c)Shiny metal sheet
- d)Unpolished wooden surface
Correct answer is option 'C'. Can you explain this answer?
In which of the following cases will regular reflection not take place when a beam of light strikes it?
a)
Marble flooring with oil spread over
b)
Mirror
c)
Shiny metal sheet
d)
Unpolished wooden surface
|
Eduskill Classes answered |
When a beam of light strikes an unpolished wooden surface, there will be a diffused reflection as an unpolished wooden surface is irregular, and not smooth.
Rearrange the following letters to make a single word and then choose the category to which it belongs:Y L A T I- a)Country
- b)Ocean
- c)City
- d)Mountain
Correct answer is option 'A'. Can you explain this answer?
Rearrange the following letters to make a single word and then choose the category to which it belongs:
Y L A T I
a)
Country
b)
Ocean
c)
City
d)
Mountain
|
|
Muskaan Joshi answered |
Answer:
To rearrange the letters "Y L A T I" into a single word, we can form the word "ITALY".
Explanation:
The word "ITALY" is the correct rearrangement of the given letters.
Category:
The word "ITALY" belongs to the category of countries.
To rearrange the letters "Y L A T I" into a single word, we can form the word "ITALY".
Explanation:
The word "ITALY" is the correct rearrangement of the given letters.
Category:
The word "ITALY" belongs to the category of countries.
Which of the following devices is used to secure tall buildings from the effect of lightning?- a)Lightning rod
- b)Electroscope
- c)Voltmeter
- d)Seismograph
Correct answer is option 'A'. Can you explain this answer?
Which of the following devices is used to secure tall buildings from the effect of lightning?
a)
Lightning rod
b)
Electroscope
c)
Voltmeter
d)
Seismograph
|
|
Coachify answered |
Lightning rod is the device used to secure tall buildings from the effect of lightning. A metal rod taller than the height of the building is installed in the walls of the building during its construction which protects the building from the effect of lightning.
A piece of clear glass and an object were placed between a lighted torch and a screen as shown in the diagram below.
A shadow was formed on the screen.Q. How could the shadow on the screen be enlarged?- a)By removing the clear glass
- b)By moving the object nearer to the screen
- c)By moving the object nearer to the clear glass
- d)By moving the torch further away from the clear glass
Correct answer is option 'C'. Can you explain this answer?
A piece of clear glass and an object were placed between a lighted torch and a screen as shown in the diagram below.
A shadow was formed on the screen.
Q. How could the shadow on the screen be enlarged?
a)
By removing the clear glass
b)
By moving the object nearer to the screen
c)
By moving the object nearer to the clear glass
d)
By moving the torch further away from the clear glass
|
Pushpa Pushpa answered |
A is the correct answer
Which of the following statement(s) about saliva is/are true?- a)Saliva helps to digest food
- b)Saliva causes food to be rolled into a ball
- c)Saliva moistens the food to make swallowing easier
- d)A and C both
Correct answer is option 'D'. Can you explain this answer?
Which of the following statement(s) about saliva is/are true?
a)
Saliva helps to digest food
b)
Saliva causes food to be rolled into a ball
c)
Saliva moistens the food to make swallowing easier
d)
A and C both
|
Geetika Patel answered |
Understanding the Role of Saliva
Saliva plays a crucial role in the digestive process and is essential for effective swallowing. Let's break down the statements regarding saliva:
Saliva Helps to Digest Food
- Saliva contains enzymes, particularly amylase, which begins the process of breaking down carbohydrates.
- This enzymatic action is essential for converting starches into simpler sugars, making it a crucial component of digestion.
Saliva Causes Food to be Rolled into a Ball
- This statement is partially true. While saliva does help in the formation of a bolus (the ball of food), it is not solely responsible for this action.
- The rolling action is primarily facilitated by the tongue, which mixes the food with saliva to form a cohesive mass.
Saliva Moistens the Food to Make Swallowing Easier
- One of the primary functions of saliva is to moisten food, making it easier to swallow.
- The lubrication provided by saliva reduces friction and allows food to slide down the esophagus smoothly.
Conclusion
Given the analysis:
- **A (Saliva helps to digest food)** is true because of the presence of digestive enzymes.
- **C (Saliva moistens the food to make swallowing easier)** is also true due to its lubricating properties.
- **B (Saliva causes food to be rolled into a ball)** is misleading since the tongue primarily performs this function with the help of saliva.
Thus, the correct answer is option 'D', as both A and C are accurate representations of saliva's functions.
Saliva plays a crucial role in the digestive process and is essential for effective swallowing. Let's break down the statements regarding saliva:
Saliva Helps to Digest Food
- Saliva contains enzymes, particularly amylase, which begins the process of breaking down carbohydrates.
- This enzymatic action is essential for converting starches into simpler sugars, making it a crucial component of digestion.
Saliva Causes Food to be Rolled into a Ball
- This statement is partially true. While saliva does help in the formation of a bolus (the ball of food), it is not solely responsible for this action.
- The rolling action is primarily facilitated by the tongue, which mixes the food with saliva to form a cohesive mass.
Saliva Moistens the Food to Make Swallowing Easier
- One of the primary functions of saliva is to moisten food, making it easier to swallow.
- The lubrication provided by saliva reduces friction and allows food to slide down the esophagus smoothly.
Conclusion
Given the analysis:
- **A (Saliva helps to digest food)** is true because of the presence of digestive enzymes.
- **C (Saliva moistens the food to make swallowing easier)** is also true due to its lubricating properties.
- **B (Saliva causes food to be rolled into a ball)** is misleading since the tongue primarily performs this function with the help of saliva.
Thus, the correct answer is option 'D', as both A and C are accurate representations of saliva's functions.
Mustard oil can be separated from water by- a)Centrifugation
- b)Elimination
- c)Decantation
- d)Sedimentation
Correct answer is option 'C'. Can you explain this answer?
Mustard oil can be separated from water by
a)
Centrifugation
b)
Elimination
c)
Decantation
d)
Sedimentation
|
Rainbow Rise Classes answered |
Mustard oil and water are immiscible and the mixture can be separated by decantation using a separating funnel.
A plane mirror reflects a pencil of light to form a real image. Then the pencil of light incident on the mirror is:- a)Divergent
- b)Convergent
- c)Parallel
- d)None of them
Correct answer is option 'B'. Can you explain this answer?
A plane mirror reflects a pencil of light to form a real image. Then the pencil of light incident on the mirror is:
a)
Divergent
b)
Convergent
c)
Parallel
d)
None of them
|
|
Varun Jain answered |
**Explanation:**
A plane mirror reflects light in such a way that the incident light rays appear to originate from behind the mirror. This creates the illusion of a virtual image, which cannot be projected onto a screen. In the case of a real image, the light rays actually converge at a point and can be projected onto a screen.
**Divergent Light Rays:**
Divergent light rays are those that spread out as they propagate. They are typically produced by a light source that emits light in all directions, such as a candle flame or a light bulb. Divergent light rays do not converge and therefore cannot form a real image.
**Convergent Light Rays:**
Convergent light rays are those that come together or converge at a point. They are typically produced by a lens or a concave mirror. Convergent light rays can form a real image when they pass through a lens or are reflected by a concave mirror.
**Parallel Light Rays:**
Parallel light rays are those that propagate in straight lines without converging or diverging. They are typically produced by a distant light source, such as the Sun. Parallel light rays do not converge and therefore cannot form a real image.
**Application to the Plane Mirror:**
A plane mirror reflects light in such a way that the angles of incidence and reflection are equal. This means that the reflected rays are parallel to the incident rays. Since parallel rays do not converge, a plane mirror cannot form a real image.
Therefore, the correct answer is option **B) Convergent**. A pencil of light incident on a plane mirror is not convergent, divergent, or parallel. It simply reflects off the mirror at the same angle as the incident angle, resulting in a virtual image.
A plane mirror reflects light in such a way that the incident light rays appear to originate from behind the mirror. This creates the illusion of a virtual image, which cannot be projected onto a screen. In the case of a real image, the light rays actually converge at a point and can be projected onto a screen.
**Divergent Light Rays:**
Divergent light rays are those that spread out as they propagate. They are typically produced by a light source that emits light in all directions, such as a candle flame or a light bulb. Divergent light rays do not converge and therefore cannot form a real image.
**Convergent Light Rays:**
Convergent light rays are those that come together or converge at a point. They are typically produced by a lens or a concave mirror. Convergent light rays can form a real image when they pass through a lens or are reflected by a concave mirror.
**Parallel Light Rays:**
Parallel light rays are those that propagate in straight lines without converging or diverging. They are typically produced by a distant light source, such as the Sun. Parallel light rays do not converge and therefore cannot form a real image.
**Application to the Plane Mirror:**
A plane mirror reflects light in such a way that the angles of incidence and reflection are equal. This means that the reflected rays are parallel to the incident rays. Since parallel rays do not converge, a plane mirror cannot form a real image.
Therefore, the correct answer is option **B) Convergent**. A pencil of light incident on a plane mirror is not convergent, divergent, or parallel. It simply reflects off the mirror at the same angle as the incident angle, resulting in a virtual image.
Study the picture below and answer the questions that follow.
Q. Which statement describe the picture correctly?- a) The process of the settling down of heavier, insoluble components in a mixture is called filtration
- b) The process of separation of soluble solids from their solutions using a filter is called filtration
- c) Evaporation of solids and leaving behind the solids
- d) A and C both
Correct answer is option 'A'. Can you explain this answer?
Study the picture below and answer the questions that follow.
Q. Which statement describe the picture correctly?
a)
The process of the settling down of heavier, insoluble components in a mixture is called filtration
b)
The process of separation of soluble solids from their solutions using a filter is called filtration
c)
Evaporation of solids and leaving behind the solids
d)
A and C both
|
|
Get Idea answered |
- Filtration uses a porous barrier (filter paper) to separate insoluble solids from a liquid.
- In the picture, the liquid (filtrate) passes through the filter paper while the solid residue remains on top.
- Settling of solids without a filter is called sedimentation, and evaporation removes a solvent, leaving dissolved solids behind—but only method A describes true filtration.
The instrument used to see above the water surface from submarine is- a)Macroscope
- b)Periscope
- c)Microscope
- d)Telescope
Correct answer is option 'B'. Can you explain this answer?
The instrument used to see above the water surface from submarine is
a)
Macroscope
b)
Periscope
c)
Microscope
d)
Telescope
|
|
Rainbow Rise Classes answered |
The instrument used to see above the water surface from submarine is called periscope.
The part of leaf through which it is attached to the stem is ____________.- a)Petiole
- b)Lamina
- c)Vein
- d)Sepal
Correct answer is option 'A'. Can you explain this answer?
The part of leaf through which it is attached to the stem is ____________.
a)
Petiole
b)
Lamina
c)
Vein
d)
Sepal
|
|
Rainbow Rise Classes answered |
The part of leaf through which it is attached to the stem is petiole.
If LINGER is coded as !@#$%& and ANGER is coded as *#$%&, then how will you code GINGER ?- a)$@#$%&
- b)!@#$%&
- c)!@#$%
- d)$#$%&
Correct answer is option 'A'. Can you explain this answer?
If LINGER is coded as !@#$%& and ANGER is coded as *#$%&, then how will you code GINGER ?
a)
$@#$%&
b)
!@#$%&
c)
!@#$%
d)
$#$%&
|
|
Aman Choudhury answered |
Understanding the Coding Scheme
To decode the given words, we need to analyze how each letter in the words corresponds to the symbols in their coded versions.
Code Analysis
- LINGER is coded as !@#$%&
Let's break it down:
- L -> !
- I -> @
- N -> #
- G -> $
- E -> %
- R -> &
- ANGER is coded as *#$%&
Analyzing this:
- A -> *
- N -> #
- G -> $
- E -> %
- R -> &
From the above, we can see that:
- The letters N, G, E, and R are consistently coded as #, $, %, and & respectively.
Decoding GINGER
Now, let's decode the word GINGER using the symbols we have identified:
- G -> $
- I -> @
- N -> #
- G -> $
- E -> %
- R -> &
Putting these together, we get:
- GINGER -> $@$#$%&
However, to match the coding style of the options provided, we can see that:
- G -> $ (Position 1)
- I -> @ (Position 2)
- N -> # (Position 3)
- G -> $ (Position 4)
- E -> % (Position 5)
- R -> & (Position 6)
The correct sequence for GINGER becomes:
- $@#$%&
Conclusion
Hence, the code for GINGER is $@#$%&, which corresponds to option A.
To decode the given words, we need to analyze how each letter in the words corresponds to the symbols in their coded versions.
Code Analysis
- LINGER is coded as !@#$%&
Let's break it down:
- L -> !
- I -> @
- N -> #
- G -> $
- E -> %
- R -> &
- ANGER is coded as *#$%&
Analyzing this:
- A -> *
- N -> #
- G -> $
- E -> %
- R -> &
From the above, we can see that:
- The letters N, G, E, and R are consistently coded as #, $, %, and & respectively.
Decoding GINGER
Now, let's decode the word GINGER using the symbols we have identified:
- G -> $
- I -> @
- N -> #
- G -> $
- E -> %
- R -> &
Putting these together, we get:
- GINGER -> $@$#$%&
However, to match the coding style of the options provided, we can see that:
- G -> $ (Position 1)
- I -> @ (Position 2)
- N -> # (Position 3)
- G -> $ (Position 4)
- E -> % (Position 5)
- R -> & (Position 6)
The correct sequence for GINGER becomes:
- $@#$%&
Conclusion
Hence, the code for GINGER is $@#$%&, which corresponds to option A.
What is the name of the process by which pure solids of copper sulphate can be obtained?- a)Crystallisation
- b)Filtration
- c)Sublimation
- d)Fraction distillation
Correct answer is option 'A'. Can you explain this answer?
What is the name of the process by which pure solids of copper sulphate can be obtained?
a)
Crystallisation
b)
Filtration
c)
Sublimation
d)
Fraction distillation
|
Tanishq Mehra answered |
The process to obtain pure solids of copper sulphate is called crystallisation.
Crystallisation is a process in which a solid substance is dissolved in a solvent to form a solution, and then the solvent is slowly evaporated or cooled down to allow the formation of pure solid crystals. This method is commonly used to purify solids and separate them from impurities.
The steps involved in the process of crystallisation are:
1. Dissolving the solid: The first step in the process is to dissolve the solid substance, in this case, copper sulphate, in a suitable solvent. The solvent used should be able to dissolve the solid at a high temperature but have a low solubility at a lower temperature. In the case of copper sulphate, water is commonly used as the solvent.
2. Heating and stirring: The mixture of the solid and solvent is heated and stirred to ensure that the solid completely dissolves in the solvent. The heating helps to increase the solubility of the solid in the solvent.
3. Filtering: After the solid is completely dissolved, the solution is filtered to remove any insoluble impurities that may be present. This step helps to obtain a clear solution.
4. Cooling or evaporation: The filtered solution is then allowed to cool down slowly or evaporate slowly. As the temperature decreases, the solubility of the solid decreases, and the solid particles start to come together to form crystals. The crystals grow over time and can be observed as the solution becomes more concentrated.
5. Separating the crystals: Once a sufficient amount of crystals has formed, they can be separated from the remaining solution. This can be done by carefully pouring off the solution or using a filter paper to collect the crystals.
6. Drying the crystals: The separated crystals are then dried to remove any remaining moisture. This can be done by placing the crystals on a filter paper or in an oven at a low temperature.
By following these steps, pure solids of copper sulphate can be obtained through the process of crystallisation. The crystals obtained are usually more pure compared to the original solid, as impurities are left behind in the solution during the filtration and crystallisation process.
Crystallisation is a process in which a solid substance is dissolved in a solvent to form a solution, and then the solvent is slowly evaporated or cooled down to allow the formation of pure solid crystals. This method is commonly used to purify solids and separate them from impurities.
The steps involved in the process of crystallisation are:
1. Dissolving the solid: The first step in the process is to dissolve the solid substance, in this case, copper sulphate, in a suitable solvent. The solvent used should be able to dissolve the solid at a high temperature but have a low solubility at a lower temperature. In the case of copper sulphate, water is commonly used as the solvent.
2. Heating and stirring: The mixture of the solid and solvent is heated and stirred to ensure that the solid completely dissolves in the solvent. The heating helps to increase the solubility of the solid in the solvent.
3. Filtering: After the solid is completely dissolved, the solution is filtered to remove any insoluble impurities that may be present. This step helps to obtain a clear solution.
4. Cooling or evaporation: The filtered solution is then allowed to cool down slowly or evaporate slowly. As the temperature decreases, the solubility of the solid decreases, and the solid particles start to come together to form crystals. The crystals grow over time and can be observed as the solution becomes more concentrated.
5. Separating the crystals: Once a sufficient amount of crystals has formed, they can be separated from the remaining solution. This can be done by carefully pouring off the solution or using a filter paper to collect the crystals.
6. Drying the crystals: The separated crystals are then dried to remove any remaining moisture. This can be done by placing the crystals on a filter paper or in an oven at a low temperature.
By following these steps, pure solids of copper sulphate can be obtained through the process of crystallisation. The crystals obtained are usually more pure compared to the original solid, as impurities are left behind in the solution during the filtration and crystallisation process.
In which of the following a permanent magnet not used?- a)Loudspeakers
- b)In magnetic door catches
- c)In compasses
- d)None of these
Correct answer is option 'D'. Can you explain this answer?
In which of the following a permanent magnet not used?
a)
Loudspeakers
b)
In magnetic door catches
c)
In compasses
d)
None of these
|
|
Parth Das answered |
Permanent Magnet
A permanent magnet is a material that produces a magnetic field and retains its magnetism over a long period of time. It is made from materials such as iron, nickel, and cobalt, which have strong magnetic properties.
Loudspeakers
In loudspeakers, a permanent magnet is used. The magnet is typically made of a material called neodymium, which is a type of rare earth magnet. The magnet is placed behind the speaker cone and interacts with an electromagnet to produce sound waves.
Magnetic Door Catches
In magnetic door catches, a permanent magnet is used. The magnet is often embedded in the door frame, while a metal plate is attached to the door. When the door is closed, the magnet attracts the metal plate, holding the door securely in place.
Compasses
In compasses, a permanent magnet is used. The magnet is typically a small, lightweight magnetized needle that is free to rotate. The needle aligns itself with the Earth's magnetic field, allowing the user to determine the direction of North.
None of these
None of these options is correct because all of them use permanent magnets. Loudspeakers use magnets to produce sound, magnetic door catches use magnets to hold doors in place, and compasses use magnets to determine direction. Therefore, the correct answer is option 'D', none of these.
A permanent magnet is a material that produces a magnetic field and retains its magnetism over a long period of time. It is made from materials such as iron, nickel, and cobalt, which have strong magnetic properties.
Loudspeakers
In loudspeakers, a permanent magnet is used. The magnet is typically made of a material called neodymium, which is a type of rare earth magnet. The magnet is placed behind the speaker cone and interacts with an electromagnet to produce sound waves.
Magnetic Door Catches
In magnetic door catches, a permanent magnet is used. The magnet is often embedded in the door frame, while a metal plate is attached to the door. When the door is closed, the magnet attracts the metal plate, holding the door securely in place.
Compasses
In compasses, a permanent magnet is used. The magnet is typically a small, lightweight magnetized needle that is free to rotate. The needle aligns itself with the Earth's magnetic field, allowing the user to determine the direction of North.
None of these
None of these options is correct because all of them use permanent magnets. Loudspeakers use magnets to produce sound, magnetic door catches use magnets to hold doors in place, and compasses use magnets to determine direction. Therefore, the correct answer is option 'D', none of these.
Which of the following statements about cooking of food are incorrect?a. It is a chemical and reversible change.
b. It is a physical and reversible change.
c. It is a physical and irreversible change.
d. It is a chemical and irreversible change.- a)a and b
- b)c and d
- c)a, b and c
- d)a, c and d
Correct answer is option 'C'. Can you explain this answer?
Which of the following statements about cooking of food are incorrect?
a. It is a chemical and reversible change.
b. It is a physical and reversible change.
c. It is a physical and irreversible change.
d. It is a chemical and irreversible change.
b. It is a physical and reversible change.
c. It is a physical and irreversible change.
d. It is a chemical and irreversible change.
a)
a and b
b)
c and d
c)
a, b and c
d)
a, c and d
|
|
Swara Chakraborty answered |
Incorrect Statements about Cooking of Food:
a. It is a chemical and reversible change.
- Cooking of food involves various chemical reactions such as denaturation of proteins, caramelization of sugars, and Maillard reaction.
- These chemical changes are irreversible, meaning the original substances cannot be obtained back once the food is cooked.
b. It is a physical and reversible change.
- Cooking of food involves the application of heat which causes physical changes like softening, melting, or evaporation.
- Most of these physical changes are reversible, as the food can often return to its original state by cooling or reheating.
c. It is a physical and irreversible change.
- This statement is incorrect because cooking of food primarily involves chemical changes along with some physical changes.
- While some physical changes may occur, the overall process of cooking results in irreversible chemical changes.
d. It is a chemical and irreversible change.
- Cooking of food does involve chemical changes, but it is not entirely a chemical change.
- Additionally, as mentioned earlier, some physical changes may occur during cooking, but the main changes are chemical and irreversible.
a. It is a chemical and reversible change.
- Cooking of food involves various chemical reactions such as denaturation of proteins, caramelization of sugars, and Maillard reaction.
- These chemical changes are irreversible, meaning the original substances cannot be obtained back once the food is cooked.
b. It is a physical and reversible change.
- Cooking of food involves the application of heat which causes physical changes like softening, melting, or evaporation.
- Most of these physical changes are reversible, as the food can often return to its original state by cooling or reheating.
c. It is a physical and irreversible change.
- This statement is incorrect because cooking of food primarily involves chemical changes along with some physical changes.
- While some physical changes may occur, the overall process of cooking results in irreversible chemical changes.
d. It is a chemical and irreversible change.
- Cooking of food does involve chemical changes, but it is not entirely a chemical change.
- Additionally, as mentioned earlier, some physical changes may occur during cooking, but the main changes are chemical and irreversible.
In which of the following cases can evaporation be helpful?- a)Cooling water in an earthen pot
- b)Obtaining salt from sea water
- c)Obtaining powdered milk from milk
- d)All of these
Correct answer is option 'D'. Can you explain this answer?
In which of the following cases can evaporation be helpful?
a)
Cooling water in an earthen pot
b)
Obtaining salt from sea water
c)
Obtaining powdered milk from milk
d)
All of these
|
|
Eduskill Classes answered |
Salt from the sea water and milk powder from the solution can be separated by evaporation.
The water evaporates, leaving behind the non-volatile solute.
Water in an earthen pot remains cool as it evaporates from the surface of the pot because evaporation has a cooling effect.
The water evaporates, leaving behind the non-volatile solute.
Water in an earthen pot remains cool as it evaporates from the surface of the pot because evaporation has a cooling effect.
Shelly is drinking orange juice and finds it sour. Which acid makes the orange juice taste sour?- a)Citric acid
- b)Acetic acid
- c)Formic acid
- d)Hydrochloric acid
Correct answer is option 'A'. Can you explain this answer?
Shelly is drinking orange juice and finds it sour. Which acid makes the orange juice taste sour?
a)
Citric acid
b)
Acetic acid
c)
Formic acid
d)
Hydrochloric acid
|
|
Rainbow Rise Classes answered |
Citric acid is responsible for the sour taste of orange juice.
Pigments of photosynthesis are present in which organelle of the plant cell?- a)Cytoplasm
- b)Chloroplast
- c)Nucleus
- d)Mitochondrion
Correct answer is option 'B'. Can you explain this answer?
Pigments of photosynthesis are present in which organelle of the plant cell?
a)
Cytoplasm
b)
Chloroplast
c)
Nucleus
d)
Mitochondrion
|
|
Rohini Seth answered |
In plants, photosynthesis takes place in chloroplasts, which contain the chlorophyll. Chloroplasts are surrounded by a double membrane and contain a third inner membrane, called the thylakoid membrane, that forms long folds within the organelle.
Which of the following condition(s) is/are essential for rusting to occur ?(a) Heat
(b) Moisture
(c) Carbon dioxide
(d) Oxygen- a)Only (b)
- b)Both (b) and (d)
- c)Only (d)
- d)Both (a) and (b)
Correct answer is option 'B'. Can you explain this answer?
Which of the following condition(s) is/are essential for rusting to occur ?
(a) Heat
(b) Moisture
(c) Carbon dioxide
(d) Oxygen
(b) Moisture
(c) Carbon dioxide
(d) Oxygen
a)
Only (b)
b)
Both (b) and (d)
c)
Only (d)
d)
Both (a) and (b)
|
|
Prasad Kulkarni answered |
Understanding Rusting
Rusting is a chemical process that occurs when iron or its alloys corrode in the presence of moisture and oxygen. To understand why option 'B' (Both (b) and (d)) is correct, let's break down the essential conditions for rusting.
Essential Conditions for Rusting
- Moisture (Water)
- Rusting requires water to initiate the reaction.
- Water acts as an electrolyte, facilitating the transfer of electrons, which is crucial for the oxidation of iron.
- Oxygen
- Oxygen in the air reacts with iron in the presence of water.
- This reaction forms iron oxide, commonly known as rust.
Other Options Explained
- Heat
- While heat can accelerate corrosion, it is not a necessary condition for rusting to occur.
- Carbon Dioxide
- Carbon dioxide is not essential for rusting. Although it can play a role in some corrosion processes, it is not a primary factor in the rusting of iron.
Conclusion
In summary, the two critical elements that must be present for rusting to occur are moisture and oxygen. Thus, the correct answer is option 'B' (Both (b) and (d)).
Rusting is a chemical process that occurs when iron or its alloys corrode in the presence of moisture and oxygen. To understand why option 'B' (Both (b) and (d)) is correct, let's break down the essential conditions for rusting.
Essential Conditions for Rusting
- Moisture (Water)
- Rusting requires water to initiate the reaction.
- Water acts as an electrolyte, facilitating the transfer of electrons, which is crucial for the oxidation of iron.
- Oxygen
- Oxygen in the air reacts with iron in the presence of water.
- This reaction forms iron oxide, commonly known as rust.
Other Options Explained
- Heat
- While heat can accelerate corrosion, it is not a necessary condition for rusting to occur.
- Carbon Dioxide
- Carbon dioxide is not essential for rusting. Although it can play a role in some corrosion processes, it is not a primary factor in the rusting of iron.
Conclusion
In summary, the two critical elements that must be present for rusting to occur are moisture and oxygen. Thus, the correct answer is option 'B' (Both (b) and (d)).
Which of the following options is FALSE?- a)A firki does not rotate in a closed area due to lack of air movement.
- b)An empty glass is not empty as it is filled with air.
- c)We see bubbles in water before it starts boiling because dissolved air is expelled out of heating.
- d)A weathercock shows the accurate speed with which the air is moving at that place.
Correct answer is option 'D'. Can you explain this answer?
Which of the following options is FALSE?
a)
A firki does not rotate in a closed area due to lack of air movement.
b)
An empty glass is not empty as it is filled with air.
c)
We see bubbles in water before it starts boiling because dissolved air is expelled out of heating.
d)
A weathercock shows the accurate speed with which the air is moving at that place.
|
|
Amar Singh answered |
Understanding Weathercocks
A weathercock, also known as a weather vane, is a device used to indicate the direction of the wind. However, it does not measure the speed of the wind accurately. Here’s why option 'D' is false:
Limitations of Weathercocks
- Weathercocks primarily indicate wind direction, not speed.
- They can only show which way the wind is blowing but do not provide quantitative data on wind velocity.
How Wind Speed is Measured
- To measure wind speed accurately, an anemometer is used.
- Anemometers consist of rotating cups or blades that turn faster with higher wind speeds, providing a numerical value for wind speed.
Common Misconceptions
- It’s a common misconception that weathercocks can indicate how fast the wind is blowing.
- While they can sway and move with the wind, their primary function is directional guidance.
Conclusion
- Therefore, option 'D' is incorrect because a weathercock does not show the accurate speed of the air movement; it only indicates the wind direction. For precise wind speed, one would need a different instrument, such as an anemometer.
A weathercock, also known as a weather vane, is a device used to indicate the direction of the wind. However, it does not measure the speed of the wind accurately. Here’s why option 'D' is false:
Limitations of Weathercocks
- Weathercocks primarily indicate wind direction, not speed.
- They can only show which way the wind is blowing but do not provide quantitative data on wind velocity.
How Wind Speed is Measured
- To measure wind speed accurately, an anemometer is used.
- Anemometers consist of rotating cups or blades that turn faster with higher wind speeds, providing a numerical value for wind speed.
Common Misconceptions
- It’s a common misconception that weathercocks can indicate how fast the wind is blowing.
- While they can sway and move with the wind, their primary function is directional guidance.
Conclusion
- Therefore, option 'D' is incorrect because a weathercock does not show the accurate speed of the air movement; it only indicates the wind direction. For precise wind speed, one would need a different instrument, such as an anemometer.
Which of the following is incorrect regarding skeletal support system of different organisms?- a)Earthworms have liquid skeleton where liquid filled spaces inside the body serve as a support system
- b)Skeletal muscles work in pairs
- c)Snakes have bristles on the under surface of the body to support movement.
- d)Birds have hollow bones with air filled cavities.
Correct answer is option 'C'. Can you explain this answer?
Which of the following is incorrect regarding skeletal support system of different organisms?
a)
Earthworms have liquid skeleton where liquid filled spaces inside the body serve as a support system
b)
Skeletal muscles work in pairs
c)
Snakes have bristles on the under surface of the body to support movement.
d)
Birds have hollow bones with air filled cavities.
|
|
Preethi Dasgupta answered |
Understanding Skeletal Support Systems
The skeletal support system varies significantly among different organisms, and option 'C' is incorrect regarding the features of snakes. Here’s an explanation of why this statement is inaccurate:
Earthworms' Liquid Skeleton
- Earthworms utilize a hydrostatic skeleton, where fluid-filled coelomic spaces provide support.
- This structure helps maintain body shape and enables movement through contraction of muscles against the liquid.
Skeletal Muscles Work in Pairs
- Muscles always function in antagonistic pairs; when one muscle contracts, the other relaxes.
- This mechanism is crucial for coordinated movement across various organisms, including humans.
Snakes and Their Movement
- The incorrect statement suggests that snakes have bristles on the undersurface for support, but this is not true.
- Snakes do not possess bristles. Instead, they rely on their flexible spine and scales for locomotion.
- Their movement involves slithering using muscle contractions and friction against the ground.
Birds' Hollow Bones
- Birds have evolved hollow bones with air-filled cavities, making them lighter for flight.
- This adaptation is essential for reducing body weight without sacrificing strength.
Conclusion
In summary, option 'C' is incorrect because snakes do not use bristles for movement; they depend on their unique anatomy and muscle coordination. Understanding these differences in skeletal systems helps appreciate how each organism adapts to its environment.
The skeletal support system varies significantly among different organisms, and option 'C' is incorrect regarding the features of snakes. Here’s an explanation of why this statement is inaccurate:
Earthworms' Liquid Skeleton
- Earthworms utilize a hydrostatic skeleton, where fluid-filled coelomic spaces provide support.
- This structure helps maintain body shape and enables movement through contraction of muscles against the liquid.
Skeletal Muscles Work in Pairs
- Muscles always function in antagonistic pairs; when one muscle contracts, the other relaxes.
- This mechanism is crucial for coordinated movement across various organisms, including humans.
Snakes and Their Movement
- The incorrect statement suggests that snakes have bristles on the undersurface for support, but this is not true.
- Snakes do not possess bristles. Instead, they rely on their flexible spine and scales for locomotion.
- Their movement involves slithering using muscle contractions and friction against the ground.
Birds' Hollow Bones
- Birds have evolved hollow bones with air-filled cavities, making them lighter for flight.
- This adaptation is essential for reducing body weight without sacrificing strength.
Conclusion
In summary, option 'C' is incorrect because snakes do not use bristles for movement; they depend on their unique anatomy and muscle coordination. Understanding these differences in skeletal systems helps appreciate how each organism adapts to its environment.
One centimeter on a scale is divided into 20 equal divisions. The least count of this scales is:- a)0.1 mm
- b)20 cm
- c)0.5 mm
- d)1 mm
Correct answer is option 'C'. Can you explain this answer?
One centimeter on a scale is divided into 20 equal divisions. The least count of this scales is:
a)
0.1 mm
b)
20 cm
c)
0.5 mm
d)
1 mm
|
Sharanya singhania answered |
According to the question 1 cm scale is divided into 20 equal divisions.
20 division = 1 cm
1 division = 1/20cm
= 0.05 cm
= 0.05×10 mm
= 0.5 mm
So, the least count of the scale is 0.5 mm
20 division = 1 cm
1 division = 1/20cm
= 0.05 cm
= 0.05×10 mm
= 0.5 mm
So, the least count of the scale is 0.5 mm
Gurpartap has 5 holidays in between every consecutive exam. The first exam is on 26th of February, which is a Friday. On which day will he have the next exam, if he has exams in a leap year?- a)2nd March
- b)3rd March
- c)4th March
- d)5th March
Correct answer is option 'B'. Can you explain this answer?
Gurpartap has 5 holidays in between every consecutive exam. The first exam is on 26th of February, which is a Friday. On which day will he have the next exam, if he has exams in a leap year?
a)
2nd March
b)
3rd March
c)
4th March
d)
5th March
|
Shiksha Academy answered |
In a leap year, there are 29 days in February. So, if he has one exam after 5 days, which are 27th, 28th, 29th, 1st and 2nd, so he will have his next exam on 3rd of March.
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