question_answer

A boy is trying to start a fire by focusing sunlight on a piece of paper using an equiconvex lens of focal length 10 cm. The diameter of the sun is \[1.39\times {{10}^{9}}m\] and its mean distance from the earth is \[1.5\times {{10}^{11}}m\]. What is the diameter of the sun's image on the paper?                                  [AIPMPT (S) 2008]

A)  \[9.2\times {{10}^{-4}}m\]      

B)       \[6.5\times {{10}^{-4}}m\]

C)  \[6.5\times {{10}^{-5}}m\]      

D)       \[12.4\times {{10}^{-4}}m\]

Correct Answer: A

Solution :

From the relation

Here,