The magnitude and direction of the current in the following circuit is :-

If the galvanometer $$G$$ does not show any deflection in the circuit shown, the value of $$R$$ is given by:

Resistance of a carbon resistor determined from colour codes is $$(22000 \pm 5 \%) \Omega$$. The colour of third band must be :

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 :