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All questions of Heat for Class 7 Exam
Conduction takes place best ina) Gases b) All of the above.c) Liquid d) None of theseCorrect answer is option 'D'. Can you explain this answer?
|
Nishanth Ghosh answered |
Conduction takes place in solids, liquids and gases, but works best in solids as their atoms/molecules are located closer together. Metals are the best solids for conducting heat. Metals have tightly packed atoms which can easily pass on their kinetic energy and also have free moving electrons. These electrons can move from the hot part of the metal to the colder part transferring the energy more quickly.
The heat in metals is conducted by the process ofA:AbsorptionB:RadiationC:ConvectionD:ConductionThe answer is D. Can you explain this?
|
Anand Choudhury answered |
The heat in metals is conducted by the process of conduction in which molecules in contact transfer heat to adjacent molecules.
Ventilation in room is due to- a)Conduction
- b)Radiation
- c)Convection
- d)Both radiation and conduction
Correct answer is 'C'. Can you explain this answer?
Ventilation in room is due to
a)
Conduction
b)
Radiation
c)
Convection
d)
Both radiation and conduction
|
Anagha Choudhury answered |
Ventilation is extremely necessary as it circulates air in the house. In this process, convection has the major role, which takes place only in liquids and gases.
There is a constant supply of fresh air and this removes the air present before. If there was no ventilation then the room might stink and there can be a feeling of stuffiness. In the room when air is hot its density decreases and rises up. So ventilators help to move out hot air from the room and lower its temperature.
One gram of ice is mixed with one gram of steam. At thermal equilibrium the temperature of mixture is- a)0°C
- b)50°C
- c)80°C
- d)100°C
Correct answer is option 'D'. Can you explain this answer?
One gram of ice is mixed with one gram of steam. At thermal equilibrium the temperature of mixture is
a)
0°C
b)
50°C
c)
80°C
d)
100°C
|
Kavya Yadav answered |
Heat required melting 1g of ice at 0 degree to water at 0 degree = 80 cal
Heat required to raise the temperature of 1 g of water from 0 degree to 100 degree = 1 x 1 x 100 =100cal
Total heat required for maximum temperature of 100 = 180 cal
1 g of steam gives 540 cal so the temperature of mixture will be 100 degrees.
Nights are cooler in the deserts because _______________ .
- a)the sky is generally cloudy.
- b)the sky is generally clear
- c)sand radiates heat more quickly as compared to earth
- d)none of these
Correct answer is option 'C'. Can you explain this answer?
Nights are cooler in the deserts because _______________ .
a)
the sky is generally cloudy.
b)
the sky is generally clear
c)
sand radiates heat more quickly as compared to earth
d)
none of these
|
Sonal Dasgupta answered |
The correct answer is Sand radiates heat more quickly than the earth.
Key Points
- Desert biomes
- Sand absorbs as well as radiates heat more quickly than the earth.
- Thus at night, the temperature of sand decreases at a much faster rate making the surroundings cooler in deserts.
- Nights are cooler in the deserts than in the plains because Sand radiates heat more quickly than the earth. Hence, Option 1 is correct.
- Because deserts have such little water vapor in the air, it makes it harder to trap heat or cold in a desert.
- At night, the sun no longer heats the desert and the heat from the day doesn't stay trapped.
- Because of this, some deserts can get cold at night, dropping to below 40F, which is coat weather.
Which of the following best describes a similarity between clinical and laboratory thermometers?- a)Both are filled with water
- b)Both are made of plastic
- c)Both are filled with mercury
- d)Both are graduated on the Fahrenheit scale
Correct answer is option 'C'. Can you explain this answer?
a)
Both are filled with water
b)
Both are made of plastic
c)
Both are filled with mercury
d)
Both are graduated on the Fahrenheit scale
|
Rohini Seth answered |
Both clinical and laboratory thermometers are made of glass and filled with mercury, which expands and contracts uniformly with temperature changes, allowing accurate readings.
Why do we feel more comfortable wearing light-colored clothes in the summer?- a)Because dark-colored clothes reflect most of the heat
- b)Because dark-colored clothes absorb more heat
- c)Because light-colored clothes trap heat better
- d)Because light-colored clothes absorb more heat
Correct answer is option 'B'. Can you explain this answer?
Why do we feel more comfortable wearing light-colored clothes in the summer?
a)
Because dark-colored clothes reflect most of the heat
b)
Because dark-colored clothes absorb more heat
c)
Because light-colored clothes trap heat better
d)
Because light-colored clothes absorb more heat
|
Bespoke Classes answered |
In the summer, we feel more comfortable wearing light-colored clothes because they reflect most of the heat that falls on them. This keeps us cooler compared to dark-colored clothes, which absorb more heat. So, when it's hot outside, light-colored clothes help us stay cool!
Glass, plastic, wood are examples of- a)Insulator
- b)Conductor
- c)Radiators
- d)Convectors
Correct answer is option 'A'. Can you explain this answer?
Glass, plastic, wood are examples of
a)
Insulator
b)
Conductor
c)
Radiators
d)
Convectors
|
Sanjana Kumar answered |
Conductors conduct electrical current very easily because of their free electrons. Insulators oppose electrical current and make poor conductors. Some common conductors are copper, aluminum, gold, and silver. Some common insulators are glass, air, plastic, rubber, and wood.
Heat of sun reaches to earth by- a)Radiation
- b)Conduction
- c)Through air.
- d)Convection
Correct answer is option 'A'. Can you explain this answer?
Heat of sun reaches to earth by
a)
Radiation
b)
Conduction
c)
Through air.
d)
Convection
|
Aditi Dey answered |
Heat of sun reaches to earth by the process of radiation as there is no medium after atmosphere to conduct heat of sun.
Temperature is measured with the help of- a)Ammeter
- b)Voltmeter
- c)Thermometer
- d)Barometer
Correct answer is option 'C'. Can you explain this answer?
Temperature is measured with the help of
a)
Ammeter
b)
Voltmeter
c)
Thermometer
d)
Barometer
|
Anita Menon answered |
Temperature is measured with the help of a thermometer.
Clinical thermometer is used to measure body temperature.
Clinical thermometer is used to measure body temperature.
Which of the following devices is used for measurement of temperature of human body?- a)Stethoscope
- b)Clinical thermometer
- c)Laboratory thermometer
- d)None of these
Correct answer is option 'B'. Can you explain this answer?
Which of the following devices is used for measurement of temperature of human body?
a)
Stethoscope
b)
Clinical thermometer
c)
Laboratory thermometer
d)
None of these
|
Maheshwar Verma answered |
To X measure temperature of human body we use clinical thermometer or doctor's thermometer.
Practice Quiz or MCQ (Multiple Choice Questions) with solutions are available for Practice, which would help you prepare for chapter Heat, Class 7, Science. You can practice these practice quizzes as per your speed and improvise the topic. Q.The heat in metals is conducted by the process of- a)Absorption
- b)Radiation
- c)Convection
- d)Conduction
Correct answer is 'D'. Can you explain this answer?
Practice Quiz or MCQ (Multiple Choice Questions) with solutions are available for Practice, which would help you prepare for chapter Heat, Class 7, Science. You can practice these practice quizzes as per your speed and improvise the topic.
Q.
The heat in metals is conducted by the process of
a)
Absorption
b)
Radiation
c)
Convection
d)
Conduction
|
Srishti Reddy answered |
The heat in metals is conducted by the process of conduction in which molecules in contact transfer heat to adjacent molecules.
The normal temperature of Human body is- a)40 ˚C
- b)35 ˚C
- c)42 ˚C
- d)37 ˚C
Correct answer is option 'D'. Can you explain this answer?
The normal temperature of Human body is
a)
40 ˚C
b)
35 ˚C
c)
42 ˚C
d)
37 ˚C
|
Ishan Gupta answered |
The average normal body temperature is generally accepted as 98.6°F (37°C). Some studies have shown that the "normal" body temperature can have a wide range, from 97°F (36.1°C) to 99°F (37.2°C). A temperature over 100.4°F (38°C) most often means you have a fever caused by an infection or illness.
Ventilation in room is due to- a)Conduction
- b)Radiation
- c)Convection
- d)Both radiation and conduction
Correct answer is option 'C'. Can you explain this answer?
Ventilation in room is due to
a)
Conduction
b)
Radiation
c)
Convection
d)
Both radiation and conduction
|
Prisha Mehta answered |
Ventilation is extremely necessary as it circulates air in the house. In this process, convection has the major role, which takes place only in liquids and gases.
There is a constant supply of fresh air and this removes the air present before. If there was no ventilation then the room might stink and there can be a feeling of stuffiness. In the room when air is hot its density decreases and rises up. So ventilators help to move out hot air from the room and lower its temperature.
In land breeze
- a)cold air moves from sea towards land during night.
- b)hot air moves from land towards sea during night.
- c)cold air moves from land towards sea during night.
- d)None of the above is correct
Correct answer is option 'C'. Can you explain this answer?
In land breeze
a)
cold air moves from sea towards land during night.
b)
hot air moves from land towards sea during night.
c)
cold air moves from land towards sea during night.
d)
None of the above is correct
|
Rahul Shah answered |
Explanation:
- Cold air moves from land towards sea during night: Land breeze occurs at night when the land cools down faster than the sea. As a result, the air above the land becomes cooler and denser, creating high pressure. The cooler air moves towards the warmer sea, creating a breeze that blows from the land towards the sea. This phenomenon is known as a land breeze.
- Cold air moves from land towards sea during night: Land breeze occurs at night when the land cools down faster than the sea. As a result, the air above the land becomes cooler and denser, creating high pressure. The cooler air moves towards the warmer sea, creating a breeze that blows from the land towards the sea. This phenomenon is known as a land breeze.
What happens when a wooden spoon is dipped in a cup of ice cream?- a)The other end becomes cold by conduction
- b)The other end becomes cold by convection
- c)The other end becomes cold by radiation
- d)The other end does not become cold
Correct answer is option 'D'. Can you explain this answer?
a)
The other end becomes cold by conduction
b)
The other end becomes cold by convection
c)
The other end becomes cold by radiation
d)
The other end does not become cold
|
Naina Iyer answered |
Explanation:
Wooden Spoon
When a wooden spoon is dipped in a cup of ice cream, the wooden material of the spoon does not conduct heat as efficiently as metal.
Insulating Properties
Wood is a poor conductor of heat compared to metal. This means that the heat from the ice cream does not transfer as easily through the wooden spoon to the other end. As a result, the other end of the spoon does not become cold when dipped in the ice cream.
Conduction, Convection, Radiation
Conduction is the transfer of heat through direct contact, but in this case, the wooden spoon does not conduct heat well. Convection is the transfer of heat through a fluid or gas, which is not applicable here. Radiation is the transfer of heat through electromagnetic waves, but the scenario described does not involve significant radiation.
Conclusion
In conclusion, when a wooden spoon is dipped in a cup of ice cream, the other end of the spoon does not become cold because wood is a poor conductor of heat. Therefore, the ice cream does not significantly affect the temperature of the entire spoon.
Wooden Spoon
When a wooden spoon is dipped in a cup of ice cream, the wooden material of the spoon does not conduct heat as efficiently as metal.
Insulating Properties
Wood is a poor conductor of heat compared to metal. This means that the heat from the ice cream does not transfer as easily through the wooden spoon to the other end. As a result, the other end of the spoon does not become cold when dipped in the ice cream.
Conduction, Convection, Radiation
Conduction is the transfer of heat through direct contact, but in this case, the wooden spoon does not conduct heat well. Convection is the transfer of heat through a fluid or gas, which is not applicable here. Radiation is the transfer of heat through electromagnetic waves, but the scenario described does not involve significant radiation.
Conclusion
In conclusion, when a wooden spoon is dipped in a cup of ice cream, the other end of the spoon does not become cold because wood is a poor conductor of heat. Therefore, the ice cream does not significantly affect the temperature of the entire spoon.
Practice Quiz or MCQ (Multiple Choice Questions) with solutions are available for Practice, which would help you prepare for chapter Heat, Class 7, Science. You can practice these practice quizzes as per your speed and improvise the topic. Q.The heat in metals is conducted by the process of- a)Absorption
- b)Radiation
- c)Convection
- d)Conduction
Correct answer is option 'D'. Can you explain this answer?
Practice Quiz or MCQ (Multiple Choice Questions) with solutions are available for Practice, which would help you prepare for chapter Heat, Class 7, Science. You can practice these practice quizzes as per your speed and improvise the topic.
Q.
The heat in metals is conducted by the process of
a)
Absorption
b)
Radiation
c)
Convection
d)
Conduction
|
Shanaya Pillai answered |
The heat in metals is conducted by the process of conduction in which molecules in contact transfer heat to adjacent molecules.
Which one is filled in the bulb of a thermometer?- a)Silver
- b)Lead
- c)Copper
- d)Mercury
Correct answer is option 'D'. Can you explain this answer?
Which one is filled in the bulb of a thermometer?
a)
Silver
b)
Lead
c)
Copper
d)
Mercury
|
Rahul Choudhury answered |
- A glass tube is filled with mercury and a standard temperature scale is marked on the tube. With changes in temperature, the mercury expands and contracts, and the temperature can be read from the scale.
- Mercury thermometers can be used to determine body, liquid, and vapor temperature.
Which of the following is a conductor of heat?
- a)Wood
- b)Plastic
- c)Iron
- d)Rubber
Correct answer is option 'C'. Can you explain this answer?
Which of the following is a conductor of heat?
a)
Wood
b)
Plastic
c)
Iron
d)
Rubber
|
Sarika mehta answered |
Conductor of Heat
Wood, plastic, iron, and rubber are all materials with different properties when it comes to conducting heat. Among these options, iron is the best conductor of heat. Here's why:
Conduction of Heat
- Heat conduction is the process where heat energy is transferred from one substance to another through direct contact.
- Materials that are good conductors of heat allow heat to pass through them easily.
Iron as a Conductor of Heat
- Iron is a metal that has a high thermal conductivity, meaning it can transfer heat efficiently.
- When heat is applied to iron, its particles vibrate and transfer the heat energy to neighboring particles quickly.
- This property is why iron is commonly used in cooking utensils, radiators, and other applications where heat transfer is necessary.
Comparison with Other Materials
- Wood and plastic are poor conductors of heat, which is why they are often used as insulating materials to prevent heat transfer.
- Rubber is also a poor conductor of heat, making it suitable for applications where heat insulation is required.
Conclusion
In conclusion, iron is the best conductor of heat among the given options. Its high thermal conductivity allows for efficient heat transfer, making it a common choice for various applications where heat conduction is essential.
Wood, plastic, iron, and rubber are all materials with different properties when it comes to conducting heat. Among these options, iron is the best conductor of heat. Here's why:
Conduction of Heat
- Heat conduction is the process where heat energy is transferred from one substance to another through direct contact.
- Materials that are good conductors of heat allow heat to pass through them easily.
Iron as a Conductor of Heat
- Iron is a metal that has a high thermal conductivity, meaning it can transfer heat efficiently.
- When heat is applied to iron, its particles vibrate and transfer the heat energy to neighboring particles quickly.
- This property is why iron is commonly used in cooking utensils, radiators, and other applications where heat transfer is necessary.
Comparison with Other Materials
- Wood and plastic are poor conductors of heat, which is why they are often used as insulating materials to prevent heat transfer.
- Rubber is also a poor conductor of heat, making it suitable for applications where heat insulation is required.
Conclusion
In conclusion, iron is the best conductor of heat among the given options. Its high thermal conductivity allows for efficient heat transfer, making it a common choice for various applications where heat conduction is essential.
Which material would you choose for the handle of a saucepan and why?- a)Metal, because it conducts heat well
- b)Plastic, because it does not conduct heat
- c)Glass, because it is transparent
- d)Copper, because it looks attractive
Correct answer is option 'B'. Can you explain this answer?
a)
Metal, because it conducts heat well
b)
Plastic, because it does not conduct heat
c)
Glass, because it is transparent
d)
Copper, because it looks attractive
|
|
Lakshya Sagare answered |
The correct answer is option B because:-
Among the given options, wood and plastic are bad conductors of heat. Copper and iron are metals which are good conductors of heat. So, the handle of a frying pan should be made from wood or plastic.
Among the given options, wood and plastic are bad conductors of heat. Copper and iron are metals which are good conductors of heat. So, the handle of a frying pan should be made from wood or plastic.
In which process is no medium required for the transfer of heat?- a)Conduction
- b)Convection
- c)Radiation
- d)Sublimation
Correct answer is option 'C'. Can you explain this answer?
In which process is no medium required for the transfer of heat?
a)
Conduction
b)
Convection
c)
Radiation
d)
Sublimation
|
Subham Nair answered |
Understanding Heat Transfer Processes
Heat can be transferred through three main processes: conduction, convection, and radiation. Each of these processes has unique characteristics regarding the medium required for heat transfer.
Conduction
- In conduction, heat is transferred through direct contact between molecules.
- This process requires a solid medium (e.g., metal) as the heat is passed from one molecule to another.
Convection
- Convection involves the transfer of heat through fluids (liquids or gases).
- It occurs when warmer areas of a fluid rise and cooler areas sink, creating a circulation pattern.
- This process also requires a medium, specifically a fluid.
Radiation
- Radiation is the only heat transfer process that does not require a medium.
- It involves the transfer of energy through electromagnetic waves, such as infrared radiation.
- Heat from the sun reaches the Earth through the vacuum of space, demonstrating that radiation can occur without any material medium.
Conclusion
- The correct answer to the question is option 'C' (Radiation) because it uniquely allows for heat transfer across empty space.
- Understanding these processes is essential in various scientific and practical applications, from cooking to climate science.
Heat can be transferred through three main processes: conduction, convection, and radiation. Each of these processes has unique characteristics regarding the medium required for heat transfer.
Conduction
- In conduction, heat is transferred through direct contact between molecules.
- This process requires a solid medium (e.g., metal) as the heat is passed from one molecule to another.
Convection
- Convection involves the transfer of heat through fluids (liquids or gases).
- It occurs when warmer areas of a fluid rise and cooler areas sink, creating a circulation pattern.
- This process also requires a medium, specifically a fluid.
Radiation
- Radiation is the only heat transfer process that does not require a medium.
- It involves the transfer of energy through electromagnetic waves, such as infrared radiation.
- Heat from the sun reaches the Earth through the vacuum of space, demonstrating that radiation can occur without any material medium.
Conclusion
- The correct answer to the question is option 'C' (Radiation) because it uniquely allows for heat transfer across empty space.
- Understanding these processes is essential in various scientific and practical applications, from cooking to climate science.
What is the sea breeze?- a)Cool air from the land moving towards the sea
- b)Warm air from the land moving towards the sea
- c)Cool air from the sea moving towards the land
- d)Warm air from the sea moving towards the land
Correct answer is option 'C'. Can you explain this answer?
What is the sea breeze?
a)
Cool air from the land moving towards the sea
b)
Warm air from the land moving towards the sea
c)
Cool air from the sea moving towards the land
d)
Warm air from the sea moving towards the land
|
Tutorpedia Coaching answered |
Cool air from the sea moving towards the land is called Sea Breeze. The cooler air from the sea rushes in towards the land to take its place.
Why are two layers of clothing warmer than a single layer of thick clothing in winter?- a)The layers trap air, which acts as an insulator
- b)The outer layer reflects heat
- c)The inner layer absorbs more body heat
- d)Two layers are always heavier than one
Correct answer is option 'A'. Can you explain this answer?
a)
The layers trap air, which acts as an insulator
b)
The outer layer reflects heat
c)
The inner layer absorbs more body heat
d)
Two layers are always heavier than one
|
Learning Education answered |
Multiple layers of clothing trap air between them, and since air is a poor conductor of heat, it acts as an insulator, keeping the body warmer.
Why should the outer walls of houses in hot climates be painted white?- a)White paint is cheaper
- b)White color reflects most of the heat
- c)White paint lasts longer
- d)White color absorbs less dust
Correct answer is option 'B'. Can you explain this answer?
a)
White paint is cheaper
b)
White color reflects most of the heat
c)
White paint lasts longer
d)
White color absorbs less dust
|
Coachify answered |
White color reflects most of the heat from the sun, helping to keep the house cooler, which is beneficial in hot climates.
Which of the following is a good conductor of heat?
- a)Wood
- b)Plastic
- c)Aluminium
- d)None of these
Correct answer is option 'C'. Can you explain this answer?
Which of the following is a good conductor of heat?
a)
Wood
b)
Plastic
c)
Aluminium
d)
None of these
|
Pallavi Banerjee answered |
Aluminum is a good conductor of heat. Aluminum has a high thermal conductivity. Wood is a poor conductor of heat (as well as other forms of energy) because it is covalently bound as a compound.
Why are stainless steel pans usually provided with copper bottoms?- a)Copper bottom makes the pan more durable
- b)Copper bottom makes the pan colorful
- c)Copper is a better conductor of heat than stainless steel
- d)Copper is easier to clean than stainless steel
Correct answer is option 'C'. Can you explain this answer?
a)
Copper bottom makes the pan more durable
b)
Copper bottom makes the pan colorful
c)
Copper is a better conductor of heat than stainless steel
d)
Copper is easier to clean than stainless steel
|
Rainbow Rise Classes answered |
Copper is a better conductor of heat than stainless steel, which allows for more even heating and better cooking efficiency.
State whether the following statement is True or FalseHeat always flows from a colder object to a hotter object.- a)True
- b)False
- c)ERROR
- d)ERROR
Correct answer is option 'B'. Can you explain this answer?
State whether the following statement is True or False
Heat always flows from a colder object to a hotter object.
a)
True
b)
False
c)
ERROR
d)
ERROR
|
Keystone Instructors answered |
- When we talk about heat, it actually flows from a hotter object to a colder object, not the other way around.
- Imagine you have a hot cup of tea and a cold ice cube.
- If you put the ice cube in the tea, the heat from the tea moves to the ice cube, making the ice cube melt.
- This shows that heat moves from hot things to cold things.
- So, the statement is False.
In which of the following materials is heat primarily transferred through conduction?- a)Liquids
- b)Gases
- c)Solids
- d)Vacuum
Correct answer is option 'C'. Can you explain this answer?
In which of the following materials is heat primarily transferred through conduction?
a)
Liquids
b)
Gases
c)
Solids
d)
Vacuum
|
|
Rohini Seth answered |
Conduction is the process by which heat is transferred from the hotter end to the colder end of an object, and in solids, the heat is generally transferred by conduction.
Chapter doubts & questions for Heat - Science Class 7 2025 is part of Class 7 exam preparation. The chapters have been prepared according to the Class 7 exam syllabus. The Chapter doubts & questions, notes, tests & MCQs are made for Class 7 2025 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests here.
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