A current loop in a magnetic field

A galvanometer having internal resistance 10 Ω requires 0.01 A for a full scale deflection. To convert this galvanometer to a voltmeter of full–scale deflection at 120V, we need to connect a resistance of

In the cyclotron, as radius of the circular path of the charged particle increases (ω = angular velocity, v = linear velocity)

In cyclotron, for a given magnet, radius of the semicircle traced by positive ion is directly proportional to
(v = velocity of positive ion)

A long wire carrying a steady current is bent into a circular loop of one turn. The magnetic field at the centre of the loop is B. It is then bent into a circular coil of n turns. The magnetic field at the centre of this coil of n turns will be

A circular loop of radius 0.3 cm lies parallel to a much bigger circular loop of radius 20 cm. The centre of the small loop is on the axis of the bigger loop. The distance between their centres is 15 cm. If a current of 2.0 A flows through the smaller loop, then the flux linked with bigger loop is

Two parallel wires 1 m apart carry currents of 1 A and 3 A respectively in opposite directions. The force per unit length acting between two wires is

Sensitivity of a moving coil galvanometer can be increased by

A range of galvanometer is ‘V’, when 50 Ω resistance is connected in series. Its range gets doubled when 500 Ω resistance is connected in series. Galvanometer resistance is

Two concentric coils each of radius equal to 2π cm are placed right angles to each other. If 3A and 4A are the currents flowing through the two coils respectively. The magnetic induction (in Wb m^–2) at the center of the coils will be