We are to find a very accurate value of a potential difference. Which type of potentiometer and driving cell should we chose?

How voltmeter and ammeter should be joined in an electric circuit?

Why voltmeter should have a very high resistance and ammeter should have a low resistance?

What are ideal cell, ideal voltmeter and ideal ammeter?

If graph shown in figure represents the $V-I$ characteristic of a device. Identify the region, if any, over which this device has a negative resistance.

The current voltage graphs for a given metallic wire at two different temperatures ${\mathrm{T}}_1$ and ${\mathrm{T}}_2$ are shown in Fig. The temperature ${\mathrm{T}}_2$ is greater than temperature ${\mathrm{T}}_1.$ State whether this statement is true or false, giving reasons in brief to support of your answer.