Sunlight of intensity $1.3 \mathrm{~kW} \mathrm{~m}^{-2}$ is incident normally on a thin convex lens of focal length $20 \mathrm{~cm}$. Ignore the energy loss of light due to the lens and assume that the lens aperture size is much smaller than its focal length. What is the average intensity of light, in $\mathrm{kW} \mathrm{m}{ }^{-2}$, at a distance $22 \mathrm{~cm}$ from the lens on the other side?

JEE · Physics · previous-year question