Questions · Page 2 of 2

1 Marks Question

Question 511 Mark
Name the type of lens which diverges a beam of parallel rays of light.
Answer
The lens which diverges a beam of parallel rays of light is a concave lens.
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Question 521 Mark
Mention the name of lens whioh can converge the sun’s rays to a point and burn a hole in the piece of paper.
Answer
Convex lens is a lens which can converge the sun’s rays to a point and burn a hole in the piece of paper.
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Question 531 Mark
State whether the following statements are True or False:
An object can be seen only if it emits light.
Answer
Fales.
An object can be seen if it reflects the light falling on it.
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Question 541 Mark
Briefly mention whether mirror change the direction of light.
Answer
Yes, when a ray of light is incident on the mirror surface, then the mirror changes the direction of light.
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Question 551 Mark
Mention the type of image formed on a cinema screen.
Answer
Real image is an image which is formed on a cinema screen.
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Question 571 Mark
When does rainbow appear in the sky?
Answer
When it is raining in one part of the sky and sunny in another, a rainbow appears.
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Question 581 Mark
Fill in the blank: The outer surface of a flat steel plate acts as a ___________ mirror.
Answer
The outer surface of a flat steel plate acts as a Plane mirror. Explanation: It acts as a plane mirror because it forms virtual, erect and same sized image of object.
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Question 601 Mark
Give the form of energy that produces the sensation of vision.
Answer
Light energy is the form of energy which produces the sensation of vision.
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Question 611 Mark
Allow the light coming out of the other face of the prism to fall on a white sheet of paper or a white wall. Explain your observation.
Answer
Different component colours of white light bend differently, and so the constituent colours can be seen separately. And the colours are said to have dispersed after passing through the prism.
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Question 621 Mark
Can you get a real image at any distance of the object from the convex mirror?
Answer
No, we cannot get a real image for any position of an object from the mirror because convex mirror always forms virtual, erect and diminished image in spite of the position of object.
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Question 641 Mark
Why is it advised not to look directly towards the Sun?
Answer
It is advised that never look directly towards the Sun or its image as it may damage our eyes.
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Question 651 Mark
What is virtual image?
Answer
The image formed by a plane mirror cannot be captured on a screen, and is called a virtual image.
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Question 661 Mark
State whether the following statements are True or False: A concave lens can be used to produce an enlarged and erect image.
Answer
False.
A concave lens can only form virtual, erect and diminished image in spite of the position of object.
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Question 671 Mark
Explain why concave mirror is known as a converging mirror.
Answer
Concave mirror is known as a converging mirror because it converges a beam of parallel rays of light (reflecting from it) at one point.
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Question 681 Mark
Fill in the blank: The inner surface of a steel spoon acts as a ___________ mirror.
Answer
The inner surface of a steel spoon acts as a Concave mirror.
It acts as a concave mirror because it forms real and virtual inverted and erect, magnified and diminished images depending upon the position of an object.
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Question 711 Mark
Name the phenomenon that is involved in the formation of image of an object by a convex lens.
Answer
Refraction of light is the name of a phenomenon which is involved in the formation of image of an object by a convex lens.
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Question 721 Mark
What happens when light rays are incident on a concave lens?
Answer
When light rays are incident on a concave lens, they bend outwards or diverge.
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Question 731 Mark
When you see yourself in the mirror, what type of image is formed?
Answer
Virtual image: An image which cannot be obtained on a screen is called a virtual image.
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Question 751 Mark
State uses of concave mirror.
Answer
Concave mirrors are used by dentists to obtain a magnified image of the teeth. They are also used in solar heaters or solar concentrators, and as reflectors in flashlights, and headlights of cars and scooters.
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Question 771 Mark
Fill in the blanks:
An image formed by a concave ___________ cannot be obtained on a screen.
Answer
An image formed by a concave lens cannot be obtained on a screen.
The image formed by concave lens is always virtual. A virtual image cannot be obtained on a screen.
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Question 781 Mark
A rotating disc has a pencil that serves as a rotator. The disc is covered with violet, indigo, blue, green, yellow, orange and red coloured papers. When the disc is rotated, it appears white instead of the individual colours. Why?
Answer
This is because a mixture of colours of the rainbow in proper proportions produces white colour.
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Question 791 Mark
What is the relation between reflection of light and the image of an object?
Answer
The bouncing of light by any smooth surface, like a mirror, is called reflection of light. Due to the reflection of light, the impression of an object formed in a mirror is called the image of the object.
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Question 801 Mark
Out of convex mirror and concave mirror, whose focus is situated behind the mirror?
Answer
The focus of convex mirror is situated behind it.
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Question 811 Mark
Briefly mention what makes things visible to us.
Answer
When a light ray falls on an object, then reflected light ray which comes from the object when A falls on our eys, allows us to see things around us.
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Question 821 Mark
Why the word $'AMBULANCE'$ is painted left-right inversed on the vehicle?
Answer
So that when the driver of a vehicle in front looks into his rear view mirror, can read ambulance written on it quickly and give way to it.
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Question 831 Mark
Why do lemons kept in a glass of water appear to be enlarged?
Answer
Water acts as a convex lens, which is a magnifying lens, due to its density. Therefore, lemons kept in water appear larger.
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Question 871 Mark
Name the phenomenon that is involved in the formation of image of an object by a concave mirror.
Answer
Reflection of light is the name of a phenomenon which is involved in the formation of image of an object by a concave mirror.
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Question 891 Mark
Give an example to show that the path of light is always straight and never curved.
Answer
Light emitted by a torch light and light emitted from the headlights of a vehicle.
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Question 901 Mark
What is image of an object?
Answer
Due to the reflection of light, the impression of an object formed in a mirror is called the image of the object.
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1 Marks Question - Page 2 - Science STD 7 Questions - Vidyadip