Current Electri...

A solenoid is at potential difference of 60 V and current flowing through it is 15 ampere, then the resistance of coil will be

All of the following statements are true except

A potential difference of V is applied at the ends of a copper wire of length land diameter d. On doubling only d, drift velocity

If the resistance of a conductor is 5 Ω at 50°C and 7Ω at 100°C, then the mean temperature coefficient of resistance of the material is

The resistance of a discharge tube is

We are able to obtain fairly large currents in a conductor because

In a wire of circular cross-section with radius r, free electrons travel with a drift velocity V when a current Iflows through the wire. What is the current in another wire of half the radius and of the same material when the drift velocity is 2V ?

The resistivity of a wire depends on its

The conductivity of a superconductor is

In a neon discharge tube 2.9 × 10¹⁸ Ne⁺ ions move to the right each second while 1.2 × 10¹⁸, electrons move to the left per second. Electron charge is 1.6 × 10^–19C.
The current in the discharge tube