Gurmit wanted to perform Activity using a laser torch. Her teacher advised her not to do so. Can you explain the basis of the teacher’s advise?

3

(a)

Explain how you can take care of your eyes.

3

(a)

What is the angle of incidence of a ray if the reflected ray is at an angle of 90° to the incident ray?

3

(a)

Boojho stands at A just on the side of a plane mirror as shown in figure. Can he see himself in the mirror? Also can he see the image of objects situated at P, Q and R?

3

(a)

(a) Find out the position of the image of an object situated at A in the plane mirror.
(b) Can Paheli at B see this image?
(c) Can Boojho at C see this image?
(d) When Paheli moves from B to C, where does the image of A move?

3

(a)

Eyes of the nocturnal birds have large cornea and a large pupil. How does this structure help them?

3

(a)

What is the difference between the surfaces of a sheet of sandpaper and a mirror?

3

(a)

Explain how do we see various objects.

3

(a)

"Though the image formation on retina is inverted but still we are able to see the erect objects". Explain how.

3

(a)

"The law of reflection only holds true for regular reflection". Is this statement true or false? Explain your answer.

3

(a)

Explain how could we can see the hair at the back of your head.

3

(a)

What is Kaleidoscope? How can it be made? What are its uses?

3

(a)

Write the structure and function of human eye.

3

(a)

What is the Braille system?

3

(a)

Rohan visited a lake on two days. On the first day, the reflection of the surrounding mountains could be seen clearly in water of the lake. On the second day, he was not able to see the reflection of the mountains clearly. Give one possible reason for this phenomenon and explain your answer clearly.

3

(a)