Monday, October 22, 2012

CBSE Class 6th Light Shadow and Reflections

Answer the following in one word

1. Light is form of what?

Ans: Energy

2.What is the speed of light?

Ans: 3 x10 m/s

3. Name the dark part of shadow?

Ans: Umbra

4.What is lighter part of shadow known as?

Ans: Penumbra

5. Are stars luminous or non luminous?

Ans: Luminous _Objects that give out or emit light of their own are called luminous objects like the sun

6. Do shadow depends on colour of objects?

Ans: No

7. Which types of object allow light to pass partially?

Ans: Translucent

Answer the following in detail

8.What are transparent, translucent and Opaque objects. Give at least two example of each?

Ans: If we cannot see through an object we call it Opaque like wood, plastic. Opaque object cannot allow 
light to pass through. If we can see through an object we call it transparent like glass, water and air . 

Transparent objects allow  light to pass through . If we can see through an object but not very clearly we call it translucent like milk, wax paper, ground glass . 
Translucent objects allow light to pass partially through.

9. Why shadow of object like aero plane or bird cannot visible on Earth?

Ans: It is because umbra region cannot able to reach earth and finish above the earth.

10. What is shadow .What are condition essential for the formation of shadow?

Ans: The dark patch that formed when opaque object come in the path of light is called shadow.
Condition essential for the formation of shadow are:

(a)Source of light (b) Opaque object (c) Screen on which shadow form

LIGHT , SHADOWS AND REFLECTIONS Hots Questions

1. In a completely dark room, can you see your face in a mirror? Why?

Ans: Due to absence of light In a dark room. Light is the source that illuminates our face by reflection.

2. Why cannot we see upside down image of the sun?

Ans: Object like sun is in infinity whose image form point sized or highly demised.

3. Why shadows are black in colour?

Ans: It is because no light reaches on screen in area where shadow form. The colour of object is colour components of light that reflect and reach our eyes.

4. Can you see an object through a “T” shaper pipe? If, no, Why?

Ans: No, it is because light always travel in straight path that is known as rectilinear properties of light.

5. Can you see a reflected light directly? If, no Why?

Ans No, the path of the ray of light is itself invisible but make the things visible only when fall on our eyes.

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