The sap of which plant is considered a good substitute for diesel oil?

Which of the following is used as a source of biodiesel in India?

What is a 'sun basket'?

Observe the figures $A$ and $B$ given below and answer the following questions.
$(i)$ The power generation by the above two methods is non-polluting. True/False.
$(ii)$ List any two applications of solar energy.
$(iii)$ What is a photovoltaic cell?

Energy from wood must be extracted more efficiently through

It is possible to extract maximum energy from wood through