Magnetic Effects of Current Test Online MCQs

1. A closely wound flat circular coil of 25 turns of wire has diameter of 10 cm which carries current of 4 amperes, the flux density at the center of a coil will be:

2. An electron moving with kinetic energy 6.6 x 10⁻¹⁴ J enters in a magnetic field of 4 x 10⁻³ T at right angles to it. The radius of its circular path will be nearest to:

3. A solenoid is 1.5 m long and its inner diameter is 4.0 cm. it has 3 layers of winding of 1000 turns each and carries a current of 2.0 amperes. The magnetic flux for a cross-section of the solenoid is nearly

4. Electron moves at right angles to a magnetic field of 1.5 x 10-2 tesla with speed of 6 x 10⁷ m/s. If the specific charge of the electron is 1.7 x 10¹¹ C/kg. The radius of circular path will be:

5. Cyclotron is used to accelerate:

6. A circular coil of radius R carries an electric current. The magnetic field due to the coil at a point on the axis of the coil located at a distance r from the center of the coil, such that r > > R, varies as

7. The magnetic moment (μ) of a revolving electron around the nucleus varies with principal quantum number n as:

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

9. The magnetic flux through a circuit carrying a current of 2.0 A is 0.8 Weber. If the current reduces to 1.5 A in 0.1 s, the induced emf be:

10. Two identical conductors of copper and aluminum are placed in an identical electric field. What is the magnitude of induced charge in the aluminum?

11. 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:

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

13. 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?

14. 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:

15. 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