How can the solar energy be used as an alternative energy​

Photovoltaic systems convert solar energy directly to electricity. Solar energy is captured using solar panels that are made of solar cells or photovoltaic cells. These cells then convert light energy from the sun into electricity.

Explanation:

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.

see earlier answer