resistance Questions

The length of a given cylindrical wire is increased by $100\%$. Due to the consequent decrease in diameter, the percentage change in the resistance of the wire will be:

A $3\text{V}$ battery with negligible internal resistance is connected in a circuit as shown. (Circuit consists of three $3\Omega$ resistors, two in parallel, then in series with the third). The current $I$ in the circuit will be:

A $220\text{volt}$, $1000\text{watt}$ bulb is connected across a $110\text{volt}$ mains supply. The power consumed will be:

A strip of copper and another of germanium are cooled from room temperature to $80\text{K}$. The resistance of: