# Math Help - energy rate query?

1. ## energy rate query?

Hi all,
Nearly all of the energy used on earth comes originally from the sun, and that solar radiation is intercepted at 1370 Wm^-^2 at the top of the atomsphere, and that 49%of this radiation is absorbed by the earths surface.

If a shallow dish containing ice or warte, placed on the earth surface, absorbs the same the same fraction of solar radiation as the surface itself, at what rate is energy absorbed from the sun by such a container of surface 0.039m^2 ?

Can you show me how thhis is worked out please.

Thanks trigger

2. Originally Posted by trigger
Hi all,
Nearly all of the energy used on earth comes originally from the sun, and that solar radiation is intercepted at 1370 Wm^-^2 at the top of the atomsphere, and that 49%of this radiation is absorbed by the earths surface.

If a shallow dish containing ice or warte, placed on the earth surface, absorbs the same the same fraction of solar radiation as the surface itself, at what rate is energy absorbed from the sun by such a container of surface 0.039m^2 ?

Can you show me how thhis is worked out please.

Thanks trigger
Energy is measured in Joules, a Watt is a Joule/second.

The dish is absorbing $49\%$ of $1370$ Watts/m^2 and its area is $0.39$ m^2 so the rate of energy absorption is:

$0.39 \times 1370 \times 0.49$ Watts

which is area times power density times efficiency.

CB