# Magnetic Effects of Current and Magnetism

### An electron, a proton and an alpha particle having the same kinetic energy

An electron, a proton and an alpha particle having the same kinetic energy are moving in circular orbits of radii re, rp, rα respectively in a uniform magnetic field B. The relation between re, rp, rα is :

1. re < rp = rα
2. re < rp < rα
3. re < rα < rp
4. re > rp = rα

### If an electron and a proton having same momenta

If an electron and a proton having same momenta enter perpendicular to a magnetic field, then

1. they will move undeflected
2. curved path of electron and proton will be same (ignoring the sense of revolution)
3. path of proton is more curved
4. curved path of electron is more curved than that of the proton

### The time period of a charged particle undergoing a circular motion

The time period of a charged particle undergoing a circular motion in a uniform magnetic field is independent of its

1. mass
2. magnetic induction
3. charge
4. speed

### If in a circular coil A of radius R, current I is flowing and in another coil

If in a circular coil A of radius R, current I is flowing and in another coil B of radius 2R a current 2I is flowing, then the ratio of the magnetic fields BA and BB, produced by them will be

1. 2
2. 1/2
3. 1
4. 1/4

### When current in a coil changes from 5 A to 2 A in 0.1 s, an average voltage of 50 V is produced

When current in a coil changes from 5 A to 2 A in 0.1 s, an average voltage of 50 V is produced. The self-inductance of the coil is:

1. 0.67 H
2. 1.67 H
3. 3 H
4. 6 H