NCERT 6th Class (CBSE) Science: Light, Shadows and Reflections

Question: Does a pinhole camra from an image or a shadow? Why?

Answer: It forms image from the light rays reflected by the object.

Question: Can you think of creating a shape that would give a circular shadow if held in one way and a rectangular shadow if held in another way?

Answer: Yes, there are many things which give a circular shadow if held in one way and a rectangular shadow if held in another way. For example: a cylinder, a circular disc etc.

 

Question: In a completely dark room, if you hold up a mirror in front of you, will you see a reflection of yourself in the mirror?

Answer: No, in a completely dark room no image will be formed because there is no light in the room so no reflection of light takes place and no image will be formed.

Question: Whether the moon is luminous or non-luminous body?

Answer: Moon is non-luminous body.

Question: What is umbra?

Answer: Umbra is the dark region behind object facing light which does not receive light at all.

Question: How does a light ray travel?

Answer: Light ray travels in a straight line.

Question: Give one natural source of light.

Answer: Sun is a natural source of light.

Question: What is shadow?

Answer: Shadow is the dark space behind an opaque object where light does not reach.

Question: What is penumbra?

Question: State difference between a luminous and a non-luminous body.

Answer: The bodies which emit light are called luminous bodies. Example: sun, stars, burning candle etc.
The bodies which does not emit light are called non-luminous bodies. Example: moon, earth, blackboard.

Question: Why is the moon not considered as a luminous body?

Answer: Moon is non-luminous body because it shines by reflecting the sunlight falling on it.

Question: What is an incandescent body? Give example.

Answer: The bodies which emit light when heated to a very high temperature are called incandescent bodies. Example: electric bulb.

Question: When does a shadow form?

Answer: Shadow is formed when light does not reach behind the opaque object kept in the path of light