If an ammeter is to be used in place of a voltmeter, then we must connect with the ammeter a -

The magnetic field at the centre of a current carrying circular loop of radius R is B₁. The magnetic field at a point on its axis at a distance R from the centre of the loop is B₂. Then the ratio (B₁ / B₂) is

The self-inductance of a solenoid of 600 turns is 108 mH. The self-inductance of a coil having 500 turns with the same length, the same radius and the same medium will be

The rms current in a circuit connected to a 50 Hz ac source is 15 A. The value of the current in the circuit $$\left( {{1 \over {600}}} \right)$$s after the instant the current is zero, is -