A boy is trying to start a fire by focusing sunlight on a piece of paper using an equiconvex lens of focal length `10cm`. The diameter of the sun is `1.39xx10^(9)m` and its mean distance from the earth is `1.5xx10^(11)m`. What is the diameter of the sun's image on the paper ?

Options

A. `6.5 xx 10^(-5)` m
B. `12.4 xx 10^(-4)`m
C. `9.2 xx 10^(-4)` m
D. `6.5 xx 10^(-4)` m

Answer

C

Explanation

Diameter of sun, O = `1.39 xx 10^(9)`
u = 1.5 `xx 10^(11) `m, v = 0.1 m
`m = (I)/(O) = (v)/(u) rArr (I)/(1.39 xx 10^(9)) = (0.1)/(1.5 xx 10^(11) )`
`I = 9.2 xx 10^(-4) `m.