The resistance of platinum wire at $$0^{\circ} \mathrm{C}$$ is $$2 ~\Omega$$ and $$6.8 ~\Omega$$ at $$80^{\circ} \mathrm{C}$$. The temperature coefficient of resistance of the wire is :

10 resistors, each of resistance $$\mathrm{R}$$ are connected in series to a battery of emf $$E$$ and negligible internal resistance. Then those are connected in parallel to the same battery, the current is increased $$n$$ times. The value of $$n$$ is :

The reciprocal of resistance is :

The distance between the two plates of a parallel plate capacitor is doubled and the area of each plate is halved. If C is its initial capacitance, its final capacitance is equal to