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. `6.5xx10^(-5)m`
B. `12.4xx10^(-4)m`
C. `9.2xx10^(-4)m`
D. `6.5xx10^(-4)m`

Answer

C

Explanation

`u=1.5xx10^(11)m`
`u=f=10cm=0.1m`
`(upsilon)/(u)=(h_(i))/(h_(0))`
`rArr" "(0.1)/(1.5xx10^(11))=(h_(i))/(1.39xx10^(9))`
`h_(i)=(1.39xx10^(8))/(1.5xx10^(11))=9.2xx10^(-4)m`