Question

Harish and his friends were excited about the news of tomorrow’s solar eclipse. Harish

convinced his friends to witness the eclipse. Harish told them that looking at the sun directly or

even into a mirror reflecting sunlight, may damage their eyes. So, Harish narrated the method to

witness to natural phenomenon in the following ways:

(i) Hold a concave mirror in hands and direct its reflecting surface towards the sun.

(ii) Direct the light reflected by the mirror on to a sheet of paper held close to the mirror.

(iii) Move the sheet of paper back and forth gradually until a bright, sharp spot of light is found

on the paper sheet, hold the mirror and the paper in the same position for a few minutes.

Read the above information and answer the following questions:

(a) What is the separation between the concave mirror and the paper sheet having a bright, sharp

spot of light in hands?

(b) Draw the ray diagram used while observing the bright, sharp spot of light in above activity.

Answer 1

(a) Here, the rays coming from the sum are coming parallel to the principal axis of the concave
mirror, so it will focus the image on its principal focus. Hence the separation between the
concave mirror and the paper sheet will be equal to the focal length of the concave mirror.

(b) Necessary ray diagram: when the object is placed between pole and mirror.
hope this helps.

Answer 2

Answer:

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