Class 12 Physics Important Chapter 6 Electromagnetic Induction

Class 12 Physics Important Chapter 6 Electromagnetic Induction Solutions English Medium As Per The New Syllabus to each chapter is provided in the list so that you can easily browse through different chapters ASSEB Class 12 Physics Additional Solutions in English and select need one. NCERT Class 12 Physics Additional Solutions Download PDF. HS 2nd Year Physics Important Solutions.

Class 12 Physics Important Chapter 6 Electromagnetic Induction

Also, you can read the NCERT book online in these sections Solutions by Expert Teachers as per Central Board of Secondary Education (CBSE) Book guidelines. CBSE Class 12 Physics Additional Question Answer are part of All Subject Solutions. Here we have given HS 2nd Physics Important Solutions English Medium for All Chapters, You can practice these here.

Electromagnetic Induction

Chapter: 6

IMPORTANT QUESTION AND ANSWER

Answer The Following Questions:

1. Write the S.I. unit of magnetic flux. Is it a scalar or a vector quantity?

Ans. The S.I. unit of magnetic flux is weber and it is scalar quantity.

2. State the factors on which the induced emf in a coil rotating in a uniform magnetic field depends.

Ans. Induced emf, epsilon = NBA ω sin ωt. Hence induced emf set up in the coil depends on (i) number of turns of the coil (ii) area of the coil (iii) angular speed of rotation of the coil and (iv) strength of the magnetic field.

3. How should a coil be moved in a uniform magnetic field so that no emf is induced in it?

Ans. ɸ = BAcosθ 

where θ is angle between normal to the plane of coil and magnetic field. If θ = 90° ɸ 

= 0 and e = 0 

For no induced emf plane of the coil should be parallel to magnetic field.

4. What is the dimensional formula for induced emf?

Ans. e = d/dt (Nɸ) = ML²T^-2A^-1.

5. A wire cuts across a flux of 0.2 * 10^{– 3} weber in 0.12 second. What is the emf induced in the wire?

Ans. Induced e.m.f. 

e = – dɸ/dt

= – 0.2 x 10^-2 /0.12 

= -0.0167 V. 

6. A magnet is moved towards a coil and an electric charge is induced in it. If the resistance of the coil is increased, how will the induced charge change?

Ans: On increasing the resistance of the coil, the magnitude of induced charge decreases.

7. Two similar circular co-axial loops carry equal currents in the same direction. If the loops be brought nearer, what will happen to the currents in them?

Ans. As the loops are brought closer, the magnetic flux linked with them increases. An emf is induced in the each loop which opposes the change in flux. So the current in each loop decreases.

8. State Lenz’s law. On which law of conservation it is based? 

Ans. Lenz’s law states that the direction of induced current is such that it opposes the cause which produces it. It is based on the law of conservation of energy.

9. Give the dimensions of Tesla.

Ans: The dimensional formula of Tesla (T) is:

M¹L^0T−2A⁻¹

10. How are eddy currents minimised in a transformer?

Ans: Eddy currents are minimised by using a laminated iron core, where each layer is insulated from the others.

11. Define mutual inductance of 1 Henry.

Ans: Mutual inductance is 1 Henry if an emf of 1 volt is induced in one coil when the current in the other coil changes at the rate of 1 ampere per second.

12. What is the unit of magnetic flux? Whether it is a vector or scalar quantity?

Ans: Unit of magnetic flux is weber (Wb). Magnetic flux is a scalar quantity.

13. Define 1 tesla. Write down the expression of Lorentz force acting on a charged particle.

Ans: 1 tesla is the magnetic field in which a particle carrying 1 coulomb of charge and moving with a velocity of 1 m/s perpendicular to the field experiences a force of 1 newton.

The Lorentz force is given by:

14. State Lenz’s Law of electromagnetic induction. Establish that it is a manifestation of the law of conservation of energy.

Ans: Lenz’s Law: The direction of induced current is such that it always opposes the change in magnetic flux that caused it.

Conservation of Energy:

Lenz’s Law ensures that if a magnet approaches a coil, the induced current creates a magnetic field opposing the motion. Hence, work must be done against this force. This mechanical work gets converted into electrical energy. If Lenz’s Law did not hold, it would violate the law of conservation of energy by allowing spontaneous energy generation without external work.

15. A coil of self-inductance 20 mH is connected to an AC source of 220 V and frequency 50 Hz. What is the inductive reactance and rms current in the circuit?

Ans: Given:

L= 20 mH =0.02 H

V = 220 V

f = 50 Hz

Inductive Reactance:

XL ​= 2π f L=2π × 50 × 0.02 = 6.28Ω

RMS Current:

I_rms =  V/X_L​ = 6.28220 ​≈ 35.03A