An alpha particle moving with certain speed towards east enters a uniform magnetic field directed vertically up. The alpha particle will then move in

The ratios of the voltage sensitivities, resistances and areas of the coils of two moving coil galvanometers $A$ and $B$ are $4: 3,3: 4$ and $1: 2$ respectively. If the number of turns of the coil of galvanometer $A$ is 200 , then the number of turns of the coil of galvanometer $B$ is (All other quantities remain same in both the cases)

A solenoid of 1000 turns per metre has a core of material with relative permeability 400 . The windings of the solenoid are insulated from the core and a current of 2 A is passed through the solenoid. Then, the value of the magnetic intensity inside the solenoid is

An emf of 2.8 mV is induced in a rectangular loop of area $150 \mathrm{~cm}^2$ when the current in the loop changes from 3 A to 8 A in a time of 0.2 s . Then, the self-inductance of the loop is