The potential difference between two points in an electric circuit is 1 V What does it mean? Name a device that helps to measure the potential difference across a conductor.
(ii) Why does the connecting cord of an - electric heater not glow while the heating element does?
(iii) Electrical resistivities of some substances at 20 °C are given as below:
(a) Among silver and copper, which one is a better conductor and why?
(b) Which material would you advise to be used in electrical heating devices and why?