Earth receives 1400 W/m^2 of solar power. If all the solar energy falling on a lens of area 0.2m^2 is focussed onto a block of ice of mass 280 grams, the time taken to melt the ice will be (Latent heat of fusion of ice =3.3×10^5 J/kg). Earth receives 1400 W/m^2 of solar power. If [...]