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Physics

# 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 $1.39 \times 10^9m$ 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 ?

$\begin {array} {1 1} (1)\;12.4 \times 10^{-4}m & \quad (2)\;9.2 \times 10^{-4}m \\ (3)\;6.5 \times 10^{-4}m & \quad (4)\;6.5 \times 10^{-5}m \end {array}$