The power rating of an electrical appliance is given by:

Two bulbs of rating $100 \mathrm{W} - 220 \mathrm{V}$ and $200 \mathrm{W} - 220 \mathrm{V}$ are connected in series to a supply of $220 \mathrm{V}$ then:

Name a metal which offers higher resistance to the passage of electricity than copper.

 Why is negligible heat produced in the connecting wires?

 Which has greater resistance $\mathit{1} \mathrm{kW}$ electric heater or a $\mathit{100} \mathrm{W}$ filament bulb both marked for $\mathit{220} \mathrm{V}$?

 A wire of uniform area of cross section is stretched to four times its original length. What factor does its resistivity change?