State whether the following statement is true or false:
Black surfaces are poor absorbers of heat.

Mention three advantages of a solar cell.

The chief constituent of biogas is methane. List any two other constituents of biogas.

Ranvir lives in a village and uses wood as a fuel. He studied in his school that charcoal is a better fuel than wood. He decided to use charcoal instead of wood.
$(a)$ How can Ranvir obtain charcoal from wood?
$(b)$ Why is charcoal considered a better fuel than wood? (Give two reasons)

Describe the steps involved in obtaining biogas and explain what is meant by anaerobic decomposition.

$A$ modern selenium solar cell can convert $25 \%$ of sunlight into electrical energy.