Which process is used to harness nuclear energy these days? Explain it briefly.

What is the basic cause for winds to blow? Name a part of India where wind energy is commercially harnessed. Compare wind power and power of water flow in respect of generating mechanical and electrical energies. What is the hindrance in developing them?

Why is a biogas plant a safe and efficient method of waste disposal? Justify.

Write the full names of $LPG$ and $CNG$.

Draw a labelled diagram of a floating gas holder type biogas plant and describe its working. Mention any two advantages of using animal dung for making biogas over using it as a fuel in the form of dried dung cakes.

$A$ student constructed a box-type solar cooker. He found that it did not work efficiently. Give any four possible mistakes in the construction and operation of the solar cooker.