Magnetic Effects of Current Test Online MCQs

1. According to Lenz’s law there is a conversion of:

2. A proton and an α-particle, moving with the same velocity, enter a uniform magnetic field, acting normal to the plane of their motion. The ratio of the radii of the circular paths described by the proton and α-particle is:

3. The magnetic moment of current (I) carrying circular coil of radius (r) and number of turns (n) varies as:

4. The earth’s magnetic field at a given point is 0.5 x 10⁻⁵ Wb m⁻². This field is to be annulled by magnetic induction at the center of a circular conducting loop of radius 5.0 cm. the current required to be flown in the loop is nearly

5. Cyclotron is used to accelerate:

6. An electron is travelling along the x-direction. It encounters a magnetic field in the y-direction. Its subsequent motion will be:

7. A coil of copper having 1000 turns is placed in a magnetic field (B=4 x 10⁻⁵) perpendicular to its axis. The cross sectional area of eh coil is 0.05 m². If it turns through 180° in 0.01 second, then the e.m.f. induced in the coil will be:

8. Two concentric coils each of radius equal to 2π cm are placed at right angles to each other. 3 ampere and 4 ampere are the currents flowing in each coil respectively. The magnetic induction in Weber/m² at the center of the coils will be (μ₀ = 4π x 10⁻⁷ Wb/A.m)

9. The cyclotron frequency of an electrons gyrating in a magnetic field of 1 T is approximately:

10. Two parallel beams of positrons moving in the same direction will:

11. What is the magnetic field at a distance R from a coil of radius r carrying current I?

12. A conducting ring of radius 1 meter is placed in an uniform magnetic field B of 0.01 teals oscillating with frequency 100 Hz with its plane at right angle to B. what will be the induced electric field?

13. Electron of mass m and charge q is travelling with a speed along a circular path of radius r at right angles to a uniform magnetic field of intensity B. If the speed of the electron is doubled and the magnetic field is halved the resulting path would have a radius

14. What should be amount of current through the rings of radius of 5 cm so that field at the center equal to the earth’s magnetic field of 7 x 10⁻⁵ Wb/ m², is

15. A 50 turn circular coil has a radius of 3 cm, it is kept in a magnetic field acting normal to the area of the coil. The magnetic field B is increased from 0.10 T in 2 milli second, the average induced emf will be: