The energy liberated by burning $1 \, g$ of wood is approximately: (in $, kJ/g$)

State the two forms in which energy is mainly utilised in our homes.

Why is $CNG$ considered an environmentally friendly fuel?

Make a list of conventional and non-conventional sources of energy. Give a brief description of harnessing one non-conventional source of energy.

The fuel used in thermal power plants is:

With the help of a labelled diagram,explain the construction and working of a solar water heater.