Physics

Problem

Earth receives

1400 \text{ W/m}^2

of solar power. If all the solar energy falling on a lens of area

0.2 \text{ m}^2

is focused on to a block of ice of mass 280 grams, the time taken to melt the ice will be... minutes. (Latent heat of fusion of ice =

3.3 \times 10^5 \text{ J/kg}