A family uses of power. (a) Direct solar energy is incident on the horizontal surface at an average rate of per square meter. If of this energy can be converted to useful electrical energy, how large an area is needed to supply 8 kW?(b) Compare this area to that of the roof of a typical house.

(a) Power used by family is given as

Solar energy received per square metre is given as

Percentage of energy converted to useful electrical energy is given as

As solar energy is incident at a rate of , the area required to generate the desired energy will be

Useful electrical energy produced per second can be calculated as,

(b) is the area needed is comparable to the roof of a large house of dimension.