Class - 5 Science Light and Shadow | Subham Sir : Free ICSE, ISC, CBSE Solutions

1. Define light.

Ans. Light is a form of energy, which makes objects visible to us.

2. Write some sources of light.

Ans. Natural source- sun, Artificial source- bulb.

3. What is a luminous object? Give example.

Ans. An object which emits its own light is called a luminous object. Example - Candle, Bulb, Sun.

4. Write nonluminous obect? Give example.

Ans. An object which can not emit its own light is called a nonluminous object. Example - Chair, Moon Plant.

5. Define bioluminescence.

Ans. Living organism when emits light due to chemical reaction inside their body is called bioluminescence. Example Firefly.

6. Why is the moon a non-luminous object?

Ans. The moon is a non-luminous object because it has no own light, it reflects the sunlight.

7. What is a Transparent object? Give example.

Ans. An object that allows light to pass completely through itself is called a transparent object.

Example - Spectacle glass, showcase glass.

8. What is an opaque object? Give example.

Ans. An object that does not allow light to pass through itself is called an opaque object.

Example- book, wall, wood. ( It casts a shadow)

9. What is a translucent object? give example.

Ans. An object that allows light partially to pass through itself is called a Translucent object.

Example- Tracing paper and bathroom windowpanes.

10. How does light propagate?

Ans. Light propagates along a straight-line path. It is called rectilinear propagation of light.

11. Define all types of the beam of light with examples.

Ans. A collection of light rays in the same direction is called a Beam of light.

PARALLEL BEAM OF LIGHT:- When rays travel parallelly the beam is called a parallel beam of light. Example - sunlight

CONVERGENT BEAM OF LIGHT:- When light rays from different directions converge a point is called a convergent beam of light. Example:- Sunlight passing through a magnifying lens.

DIVERGENT BEAM OF LIGHT:- When light rays from a point diverge in different directions is called a divergent beam of light. Example:- Bulb

12. Define shadow.

Ans. A dark spot formed when the way of light is blocked by an opaque substance is called shadow.

13. Write the properties of a shadow.

Ans. i) Formed opposite site of source of light.

ii) Dark in colour.

iii) Always the same shape of the object.

iv) Same or different size of the object

v) The shadow moves with a moving object.

14. What things are essential for a shadow?

Ans: i) Light source

ii) Screen

iii) Object

15. Define the length of shadow during different times of the day?

Ans: i) Shorter at noon.

ii) Longer in the morning and evening.

16. What is Eclipse?

Ans. In the phenomenan where earth forms a shadow on moon or Moon forms a shadow on earth.

17. Write the difference between a solar eclipse and a lunar eclipse.

Ans:

Solar eclipse	Lunar eclipse
1. The moon is in the middle of the sun and earth.	Earth is in the middle of the sun and moon.
2. It occurs in the daytime.	It occurs at night time.
3. Should not observe with the naked eye.	It can be observed with the naked eye.

18. How many types of solar eclipse?

Ans: i) Total solar eclipse ( The sun is completely covered by the moon.)

ii) Partial solar eclipse ( The sun is partially covered by the moon.)

iii) Annular solar eclipse ( Sun is not completely covered by the moon. Diamond ring is formed.)

19. How many types of lunar eclipse?

Ans: i) Total lunar eclipse ( Moon is not visible to people on the earth.)

ii) Partial lunar eclipse ( Moon becomes partially visible from Earth.)

iii) Penumbral lunar eclipse ( Moon passes through the penumbra of earth.)

20. Can you see the shadow of a bird flying very high in the sky?

Ans. The birds flying in the sky do not cast their shadow on the earth because the umbra is absent and the penumbra is too large and too faint so that it is not visible .