All Exams >
Grade 4 >
Science for Grade 4 >
All Questions
All questions of Light & Sound for Grade 4 Exam
Q can hear the sound made by P in the shortest time, when the medium is a _______.- a)Brick wall
- b)Water
- c)Air
- d)Vacuum
Correct answer is option 'A'. Can you explain this answer?
Q can hear the sound made by P in the shortest time, when the medium is a _______.
a)
Brick wall
b)
Water
c)
Air
d)
Vacuum
|
Anjali Gupta answered |
Sound waves travel fastest in solid medium.
Nidhi was asked to draw the shadow of a tumbler formed on the screen behind it, when it is kept in different manners at the same position and light is shone on it from the same direction. She drew three shadows as shown here.
Read the following statements regarding it and select the INCORRECT ones.
(i) Shadow 1 is formed when the tumbler is kept horizontally.
(ii) Shadow 2 is formed when the tumbler is kept vertically upright.
(iii) Shadow 3 is incorrect because the given tumbler cannot cast a rectangular shadow.- a)(i) and (ii) only
- b)(ii) and (iii) only
- c)(i) and (iii) only
- d)None of these
Correct answer is option 'D'. Can you explain this answer?
Nidhi was asked to draw the shadow of a tumbler formed on the screen behind it, when it is kept in different manners at the same position and light is shone on it from the same direction. She drew three shadows as shown here.
Read the following statements regarding it and select the INCORRECT ones.
(i) Shadow 1 is formed when the tumbler is kept horizontally.
(ii) Shadow 2 is formed when the tumbler is kept vertically upright.
(iii) Shadow 3 is incorrect because the given tumbler cannot cast a rectangular shadow.
Read the following statements regarding it and select the INCORRECT ones.
(i) Shadow 1 is formed when the tumbler is kept horizontally.
(ii) Shadow 2 is formed when the tumbler is kept vertically upright.
(iii) Shadow 3 is incorrect because the given tumbler cannot cast a rectangular shadow.
a)
(i) and (ii) only
b)
(ii) and (iii) only
c)
(i) and (iii) only
d)
None of these
|
|
Anjali Gupta answered |
A tumbler or any object may cast differently shaped shadows depending upon the angle of light source and the manner in which the object is kept.
Roy wants to make a list of actions that show friction produces heat. Which of the following could he include in his list?
(a) Rubbing hands together
(b) Scratching a match stick against the box
(c) Sawing wood
(d) Drilling a hole into metal sheet
(e) Rubbing off some pencil marks with an eraser- a)(a) and (e) only
- b)(a), (b) and (e) only
- c)(a), (b), (c) and (e) only
- d)(a), (b), (c), (d) and (e)
Correct answer is option 'D'. Can you explain this answer?
Roy wants to make a list of actions that show friction produces heat. Which of the following could he include in his list?
(a) Rubbing hands together
(b) Scratching a match stick against the box
(c) Sawing wood
(d) Drilling a hole into metal sheet
(e) Rubbing off some pencil marks with an eraser
(a) Rubbing hands together
(b) Scratching a match stick against the box
(c) Sawing wood
(d) Drilling a hole into metal sheet
(e) Rubbing off some pencil marks with an eraser
a)
(a) and (e) only
b)
(a), (b) and (e) only
c)
(a), (b), (c) and (e) only
d)
(a), (b), (c), (d) and (e)
|
Rhea Reddy answered |
As all these actions involve two surfaces rubbing against each other, thus force of friction comes into action which produces heat.
Electrical appliances and switches should be only tested with- a)wet hands
- b)screw
- c)Knife
- d)tester
Correct answer is option 'D'. Can you explain this answer?
Electrical appliances and switches should be only tested with
a)
wet hands
b)
screw
c)
Knife
d)
tester
|
Nclex Coaching Centre answered |
Why should electrical appliances and switches be tested with a tester?
- Safety: Testing electrical appliances and switches with a tester ensures that they are functioning correctly and are safe to use.
- Avoid Electric Shock: Using a tester helps in identifying any faults or malfunctions in the appliance or switch, reducing the risk of electric shock.
- Proper Functionality: Testing with a tester ensures that the appliance or switch is working as intended and will not cause any electrical hazards.
- Prevent Damage: Regular testing with a tester can help in identifying any issues early on, preventing further damage to the appliance or switch.
- Compliance: Testing with a tester is often a requirement to ensure compliance with safety regulations and standards.
By using a tester to check electrical appliances and switches, you can ensure the safety of yourself and others around you, prevent damage to the appliances, and comply with safety standards.
Ashish shone a torch at a ball. The shadow of the ball is projected onto a screen as shown.
What could Ashish do to get a smaller shadow of the ball on the screen?
1. Move the ball closer to the screen.
2. Move the torch further away from the ball.
3. Move the screen further away from the ball.- a)1 only
- b)3 only
- c)1 and 2 only
- d)2 and 3 only
Correct answer is option 'C'. Can you explain this answer?
Ashish shone a torch at a ball. The shadow of the ball is projected onto a screen as shown.
What could Ashish do to get a smaller shadow of the ball on the screen?
1. Move the ball closer to the screen.
2. Move the torch further away from the ball.
3. Move the screen further away from the ball.
What could Ashish do to get a smaller shadow of the ball on the screen?
1. Move the ball closer to the screen.
2. Move the torch further away from the ball.
3. Move the screen further away from the ball.
a)
1 only
b)
3 only
c)
1 and 2 only
d)
2 and 3 only
|
|
Anjali Gupta answered |
By increasing the distance between light source and object the size of the shadow can be reduced. The distance between them can be increased either by moving ball closer to the screen or by moving torch further away from the ball.
When an object is nearer to the source of light, it will cast a ________________ shadow.- a)short
- b)curved
- c)round
- d)bigger
Correct answer is option 'D'. Can you explain this answer?
When an object is nearer to the source of light, it will cast a ________________ shadow.
a)
short
b)
curved
c)
round
d)
bigger
|
Glitz Classes answered |
Explanation:
- Shadow Size: When an object is closer to the source of light, it will cast a bigger shadow. This is because the closer an object is to the light source, the larger the shadow it will create.
- Light Rays: Light rays from the source spread out as they move away, so when an object is closer, it blocks more of these rays, creating a larger shadow.
- Distance: The distance between the object and the surface on which the shadow is cast also plays a role in determining the size of the shadow. The closer the object is to the surface, the larger the shadow will appear.
- Shape of the Shadow: The shape of the shadow may vary depending on the shape of the object and the angle at which the light is hitting it, but the size will generally be larger when the object is closer to the light source.
Select the forces that the women X and Y in the diagram need to overcome to carry their groceries.
- a)a
- b)b
- c)c
- d)d
Correct answer is option 'B'. Can you explain this answer?
Select the forces that the women X and Y in the diagram need to overcome to carry their groceries.
a)
a
b)
b
c)
c
d)
d
|
Pranav Singh answered |
Woman 'X' needs to overcome friction to slide the trolley smoothly. Woman 'Y' needs to hold up the shopping bags against gravity,
Mirror is __________.- a)Transparent object
- b)Translucent Object
- c)Opaque Object
- d)None of the above
Correct answer is option 'C'. Can you explain this answer?
Mirror is __________.
a)
Transparent object
b)
Translucent Object
c)
Opaque Object
d)
None of the above
|
|
Nclex Coaching Centre answered |
Explanation:
- Mirror is an Opaque Object: Mirrors are considered opaque objects because they do not allow light to pass through them. When light hits the mirror, it is reflected back, creating an image. This property of reflecting light makes mirrors useful for various purposes like seeing ourselves, applying makeup, or even in scientific experiments.
_____________ force is also called opposing force.- a)Frictional Force
- b)Gravitational force
- c)Muscular forceE
- d)lectrostatic force
Correct answer is option 'A'. Can you explain this answer?
_____________ force is also called opposing force.
a)
Frictional Force
b)
Gravitational force
c)
Muscular forceE
d)
lectrostatic force
|
Kds Coaching answered |
- Opposing Force: The force that acts in the opposite direction to the motion of an object is called opposing force.
- Gravitational Force: Gravitational force is the force of attraction between two masses. It always acts downwards towards the center of the Earth.
- Frictional Force: Frictional force is the force that opposes the motion of an object when it is in contact with another surface. It acts in the opposite direction to the direction of motion.
- Muscular Force: Muscular force is the force generated by muscles in the body. It can be used to lift objects, push or pull things, and perform various physical activities.
- Electrostatic Force: Electrostatic force is the force between electrically charged objects. Like charges repel each other, and opposite charges attract each other.
- From the given options, the force that is also known as the opposing force is the Frictional Force. Frictional force acts in the opposite direction to the motion of an object and opposes its movement. It is commonly experienced in everyday life when objects slide or move against each other.
_______________ is a luminous body.- a)Plants
- b)Books
- c)Star
- d)Moon
Correct answer is option 'C'. Can you explain this answer?
_______________ is a luminous body.
a)
Plants
b)
Books
c)
Star
d)
Moon
|
Sankar Yadav answered |
Star is a luminous body
Luminous Body Explanation:
Definition:
A luminous body is an object that emits light, either through its own energy source or by reflecting light from another source.
Example:
- Stars are one of the most common examples of luminous bodies in the universe. They emit light and heat through nuclear fusion reactions in their cores.
- Other examples of luminous bodies include light bulbs, the sun, and certain types of fish that produce their own light through bioluminescence.
Characteristics:
- Luminous bodies are visible in the dark because they emit their own light.
- They can vary in size, temperature, and brightness.
- The intensity of light emitted by a luminous body depends on factors such as its energy source and distance from the observer.
In conclusion, stars are considered luminous bodies because they emit light and heat through their own energy sources. They play a crucial role in the universe by providing light, heat, and energy to planets and other celestial bodies.
Refer to the given figure and select the correct option.
- a)If W = X, box will move towards W.
- b) If W > X, the box will move towards X.
- c)If W = X, the box will move towards X.
- d)If W < X, the box will move towards X.
Correct answer is option 'B'. Can you explain this answer?
Refer to the given figure and select the correct option.
a)
If W = X, box will move towards W.
b)
If W > X, the box will move towards X.
c)
If W = X, the box will move towards X.
d)
If W < X, the box will move towards X.
|
|
Anjali Gupta answered |
When a pushing force is applied, the object moves farther from the source of force. In case of opposing forces the object moves towards the weaker force. In case both the forces are equal, object shows no movement at all.
The girl a is putting more efforts to pull the sack bag as compared to the girl b. Girl a has to work more against a force which also _______.- a)Changes the direction of a moving object
- b)Causes all objects to fall to the ground
- c)Prevents us from slipping when we walk
- d)Makes a stationary object to move
Correct answer is option 'C'. Can you explain this answer?
The girl a is putting more efforts to pull the sack bag as compared to the girl b. Girl a has to work more against a force which also _______.
a)
Changes the direction of a moving object
b)
Causes all objects to fall to the ground
c)
Prevents us from slipping when we walk
d)
Makes a stationary object to move
|
|
Pranav Singh answered |
Wheel cart reduces friction between sack bag and floor making it easier to pull the bag. Friction is present between a surface and object put on it and resists its motion. Friction is the force which prevents us from slipping when we walk.
The above figures show the force required to move a 100 g object over different surfaces. The friction is greatest at ____.- a)Surface W
- b)Surface X
- c)Surface Y
- d)Surface Z
Correct answer is option 'A'. Can you explain this answer?
The above figures show the force required to move a 100 g object over different surfaces. The friction is greatest at ____.
a)
Surface W
b)
Surface X
c)
Surface Y
d)
Surface Z
|
|
Pranav Singh answered |
Friction is a force or resistance offered by a surface to the movement of object in contact. As it is shown, that on surface W, the force required to move an object is maximum, this shows that the opposing force of friction is provided maximum by surface W.
Chapter doubts & questions for Light & Sound - Science for Grade 4 2025 is part of Grade 4 exam preparation. The chapters have been prepared according to the Grade 4 exam syllabus. The Chapter doubts & questions, notes, tests & MCQs are made for Grade 4 2025 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests here.
Chapter doubts & questions of Light & Sound - Science for Grade 4 in English & Hindi are available as part of Grade 4 exam.
Download more important topics, notes, lectures and mock test series for Grade 4 Exam by signing up for free.
Science for Grade 4
25 videos|44 docs|24 tests
|
|
© EduRev
|
Education Revolution
|
|
Signup to see your scores
go up within 7 days!
Access 1000+ FREE Docs, Videos and Tests
Takes less than 10 seconds to signup