Why do we use Nichrome as a heating element?

In the circuit shown, the heat produced in $5 \mathrm{\Omega }$ resistor is $10 \mathrm{cal} {\mathrm{s}}^{-1}$. The heat produced per sec in $4 \mathrm{\Omega }$ resistor will be

Give three characteristics of the material for the heating element.

Find the ratio of resistances for two bulbs of $220 \mathrm{V}-60 \mathrm{W} \mathrm{and} 110 \mathrm{V}-60 \mathrm{W}$.

Write joule's law related to the heating effect of the current.

Correct the statements by modifying the underlined words appropriately if it is wrong.

In the incandescent lamps, vaporisation of filaments can be reduced by using hydrogen or nitrogen at low pressure.

Solder is an alloy of lead and tin.

State one important use of water.