1What is solar energy? How is it used directly and indirectly?
2What is thermonuclear fusion? Write its three steps with equations.
3What are the conditions in the sun that make thermonuclear fusion possible?
4Why is the sun regarded as the prime source of power?
5Explain how hydroelectricity is obtained indirectly from solar energy.
6How can we say that fossil fuels are a product of solar power?
7How is wind energy produced? Show that it is a product of solar energy.
8Calculate the energy released if 0.2 g of mass is destroyed in a nuclear reaction.
9What are isotopes? Name the isotopes of hydrogen.