Name the largest component of biogas.

Name the places of our country where fields of natural gas are found. Why is it called a clean fuel? Give two reasons.

Enlist the energy changes taking place in a hydroelectric power station.

Draw the diagram of the floating gas holder type biogas plant and mark on it the gas outlet.

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.

Amount of charcoal produced on the destructive distillation of $1 \, kg$ of wood is about: (in $, kg$)