Electromagnetic Induction and Electromagnetic Waves

Physics, SSC-Punjab Class 10. This chapter is split into 40 topics and has 1,004 practice questions. The topics covered are listed below, followed by 10 free sample questions from the chapter.

Topics in this chapter

1. Deflection of an electron beam by an electric field 24 questions
2. Electromagnetic induction basics 30 questions
3. Faraday's law numericals: flux, time and turns 24 questions
4. Deflection of an electron beam by a magnetic field 22 questions
5. Speed of electromagnetic waves and travel times 25 questions
6. Wave equation for electromagnetic waves: c = f lambda 24 questions
7. Transformer numericals: secondary voltage 30 questions
8. CRO time base, saw-tooth wave and waveforms 23 questions
9. Induced e.m.f. in a moving wire 30 questions
10. Slip rings and brushes in a generator 21 questions
11. Transformer numericals: turns ratio and type 27 questions
12. Scattering of light: why the daytime sky is blue 23 questions
13. A.C. generator e.m.f. graph and coil positions 30 questions
14. Power loss in transmission cables: numericals 23 questions
15. Ideal transformer: power and current relations 22 questions
16. Transformer: working, iron core and A.C. only 23 questions
17. Transformer numericals: number of turns 30 questions
18. Lenz's law: direction of induced current in a coil 21 questions
19. A.C. generator: construction and parts 30 questions
20. Step-up and step-down transformers 25 questions
21. Reading a CRO trace: period, frequency and voltage 30 questions
22. Photoelectric effect and solar sails 22 questions
23. A.C. generator: working and energy conversion 30 questions
24. Faraday's law numericals: induced e.m.f. 24 questions
25. Transformer: construction and principle 23 questions
26. Transformer problems: mixed and integrated 22 questions
27. Photons and the particle nature of light 23 questions
28. Scattering of light: red colour of sunrise and sunset 22 questions
29. Lenz's law and conservation of energy 28 questions
30. Induced e.m.f. and current in a loop 23 questions
31. Electromagnetic waves: nature, properties and uses 24 questions
32. High-voltage transmission and power loss in cables 23 questions
33. Magnetic flux numericals 29 questions
34. Cathode ray oscilloscope: purpose and structure 28 questions
35. Factors affecting the size of the induced e.m.f. 21 questions
36. Induction and waves: mixed reasoning 23 questions
37. Magnetic flux: definition, unit and formula 25 questions
38. Scattering of light: spectrum, wavelengths and reasoning 21 questions
39. Frequency and period of the generated A.C. 26 questions
40. Faraday's law of electromagnetic induction 30 questions

Sample questions: Electromagnetic Induction and Electromagnetic Waves

10 sample questions with the correct answer and an explanation. Try to answer each one before reading the explanation.

Q1. The north pole of a bar magnet is moved away from a coil connected to a galvanometer. What polarity does the end of the coil nearest the magnet take up?

• A. No pole at all, because the coil is not made of a magnetic material
• B. South pole, because the induced current opposes the motion of the magnet(correct answer)
• C. North pole, because the induced current helps the motion of the magnet
• D. South pole, because the induced current helps the motion of the magnet

Answer: B.The north pole away from the coil makes the near end south: Lenz's law requires the induced field to oppose the motion (flux through the coil is decreasing).

Q2. The south pole of a bar magnet is moved away from a coil connected to a galvanometer. What polarity does the end of the coil nearest the magnet take up?

• A. South pole, because the induced current helps the motion of the magnet
• B. No pole at all, because the coil is not made of a magnetic material
• C. North pole, because the induced current opposes the motion of the magnet(correct answer)
• D. North pole, because the induced current helps the motion of the magnet

Answer: C.The south pole away from the coil makes the near end north: Lenz's law requires the induced field to oppose the motion (flux through the coil is decreasing).

Q3. An electron beam moves to the right through a uniform magnetic field directed into the page. In which direction is the beam deflected?

• A. To the left
• B. Upwards
• C. Downwards(correct answer)
• D. To the right

Answer: C.For a negative charge the force is −e(v × B). With v to the right and B into the page, the deflection is downwards (standard vector rule, consistent with Fleming's left-hand rule).

Q4. A beam of electrons travelling to the right in the plane of the page enters a uniform magnetic field pointing out of the page. The force on the beam is directed:

• A. Downwards
• B. To the left
• C. Upwards(correct answer)
• D. To the right

Answer: C.For a negative charge the force is −e(v × B). With v to the right and B out of the page, the deflection is upwards (standard vector rule, consistent with Fleming's left-hand rule).

Q5. An electron beam moves to the left through a uniform magnetic field directed into the page. In which direction is the beam deflected?

• A. Downwards
• B. To the right
• C. To the left
• D. Upwards(correct answer)

Answer: D.For a negative charge the force is −e(v × B). With v to the left and B into the page, the deflection is upwards (standard vector rule, consistent with Fleming's left-hand rule).

Q6. A beam of electrons travelling to the left in the plane of the page enters a uniform magnetic field pointing out of the page. The force on the beam is directed:

• A. Upwards
• B. To the left
• C. To the right
• D. Downwards(correct answer)

Answer: D.For a negative charge the force is −e(v × B). With v to the left and B out of the page, the deflection is downwards (standard vector rule, consistent with Fleming's left-hand rule).

Q7. An electron beam moves upwards through a uniform magnetic field directed into the page. In which direction is the beam deflected?

• A. Downwards
• B. Upwards
• C. To the left
• D. To the right(correct answer)

Answer: D.For a negative charge the force is −e(v × B). With v upwards and B into the page, the deflection is to the right (standard vector rule, consistent with Fleming's left-hand rule).

Q8. A beam of electrons travelling upwards in the plane of the page enters a uniform magnetic field pointing out of the page. The force on the beam is directed:

• A. Upwards
• B. Downwards
• C. To the right
• D. To the left(correct answer)

Answer: D.For a negative charge the force is −e(v × B). With v upwards and B out of the page, the deflection is to the left (standard vector rule, consistent with Fleming's left-hand rule).

Q9. An electron beam moves downwards through a uniform magnetic field directed into the page. In which direction is the beam deflected?

• A. To the left(correct answer)
• B. To the right
• C. Downwards
• D. Upwards

Answer: A.For a negative charge the force is −e(v × B). With v downwards and B into the page, the deflection is to the left (standard vector rule, consistent with Fleming's left-hand rule).

Q10. A beam of electrons travelling downwards in the plane of the page enters a uniform magnetic field pointing out of the page. The force on the beam is directed:

• A. Upwards
• B. To the left
• C. To the right(correct answer)
• D. Downwards

Answer: C.For a negative charge the force is −e(v × B). With v downwards and B out of the page, the deflection is to the right (standard vector rule, consistent with Fleming's left-hand rule).