- 1. Define the following terms:
(i) Magnetic flux density
(ii) Relative permeability
(iii) Absolute permeability
(iv) Magnetomotive force.
- 2. State the differences between magnetically soft and magnetically hard materials.
- 3. Sketch the shape of magnetic field around a current-carrying conductor. How can the direction of the field be determined?
- 4. What do you understand by the ferromagnetic, paramagnetic and-diamagnetic materials?
- 5. Sketch the magnetic field that occurs around two adjacent current carrying conductors
(i) for currents in opposite direction
(ii) for currents in the same direction.
- 6. Derive an expression for magnetising force of a long straight conductor.
- 7. Derive an expression for magnetising force of a long solenoid.
- 8. Derive an expression for force between two parallel conductors.
- 9. Define the following terms as applied to a magnetic circuit:
Permeability; Magnetomotive force (m.m.f.) ; Reluctance; Permeance ; Reluctivity.
- 10. Give the analogy between electric and magnetic circuits (similarities).
- 11. What do you mean by magnetic leakage and fringing?
- 12. Draw and explain a magnetising curve for a ferromagnetic material.
- 13. Explain briefly the following two types of losses which occur when magnetic materials are subjected to an alternating flux:
(i) Hysteresis loss
(ii) (ii) Eddy current loss.
- 14. What do you understand by “electromagnetic induction”.
- 15. Explain briefly Faraday’s first and second laws of electromagnetic induction.
- 16. State and explain Fleming’s right hand rule.
- 17. What is “Lenz’s law”?
- 18. What is difference between the dynamically and statically induced e.m.fs. ?
- 19. Define the term “Self-inductance”.
- 20. Derive an expression for energy stored in an electromagnetic field.
- 21. Explain briefly “Mutually induced e.m.f.”.
- 22. What is “Mutual inductance”?
- 23. What do you understand by “Co-efficient of coupling”?