The resistances of a wire at temperatures $t\,^oC$ and $0\,^oC$ are related by:

Which of the following has a negative temperature coefficient?

An electric toaster has a resistance of $60 \ \Omega$ at room temperature $\left(27^{\circ} C\right)$. The toaster is connected to a $220 \ V$ supply. If the current flowing through it reaches $2.75 \ A$,the temperature attained by the toaster is around: (given $\alpha = 2 \times 10^{-4} /{ }^{\circ} C$) (in $^{\circ} C$)

The reciprocal of resistance is

The specific resistance of a wire is $\rho$,its volume is $3\,m^3$ and its resistance is $3\,\Omega$. Then its length will be:

$A$ metal rod of length $10 \text{ cm}$ and a rectangular cross-section of $1 \text{ cm} \times 0.5 \text{ cm}$ is connected to a battery across opposite faces. The resistance will be