The resistance of a wire is $20 \Omega$. It is stretched,so that the length becomes three times,then the new resistance of the wire will be (in $Omega$)

The resistance of the bulb filament is $100 \ \Omega$ at a temperature of $100^{\circ} C$. If its temperature coefficient of resistance is $0.005 \ ^{\circ} C^{-1}$,at what temperature will its resistance become $200 \ \Omega$ (in $^{\circ} C$)?

Wires $P$ and $Q$ have the same resistance at ordinary (room) temperature. When heated,the resistance of $P$ increases and that of $Q$ decreases. We conclude that:

If the masses of three wires of same material are in the ratio of $1: 2: 3$ and their lengths are in the ratio of $3: 2: 1$,then electrical resistances of these wires are in the ratio

The length and area of cross-section of a copper wire are respectively $30 \ m$ and $6 \times 10^{-7} \ m^2$. If the resistivity of copper is $1.7 \times 10^{-8} \ \Omega \ m$,then the resistance of the wire is (in $Omega$)

The resistance of a conductor at $15^{\circ}C$ is $16\, \Omega$ and at $100^{\circ}C$ is $20\, \Omega$. What will be the temperature coefficient of resistance of the conductor?