ECAT Physics — Electromagnetic Induction
Electromagnetic Induction is part of the Physics section of the UET ECAT (30 of the 100 MCQs). It breaks into 4 subtopics, and we hold 27 ECAT-pattern practice MCQs on it, each with a written explanation. Tap a subtopic below to practise just that.
Subtopics (4)
How Electromagnetic Induction is tested
Across the 7 ECAT past papers on ParhaiKrlo, Electromagnetic Induction accounts for 10 questions. It appears in 6 of them, about 1.7 questions a paper. The heaviest was ECAT Past Paper 07, with 2 questions.
| Paper | Questions |
|---|---|
| ECAT Past Paper 07 | 2 |
| ECAT Past Paper 05 | 2 |
| ECAT Past Paper 04 | 2 |
| ECAT Past Paper 03 | 1 |
| ECAT Past Paper 02 | 1 |
| ECAT Past Paper 01 | 2 |
Electromagnetic Induction MCQs from the ECAT past papers
Try each one before opening the answer. Each comes with a short explanation.
- Q1 · ECAT Past Paper 07 · Electromagnetic Induction
You have 20 inductors, each of 15 H (no mutual inductance). You need an inductance of 1 H in a circuit. You can achieve it by connecting:
- A.15 inductors in parallel
- B.20 inductors in series
- C.15 inductors in series
- D.20 inductors in parallel
Show answer
Answer: A. 15 inductors in parallel — Equal inductors in parallel give L/n: 15 H/15 = 1 H.
- Q2 · ECAT Past Paper 05 · Electromagnetic Induction
You have 20 inductors, each of 15 H (no mutual inductance). You need an inductance of 1 H. You can achieve it by connecting:
- A.15 inductors in parallel
- B.15 inductors in series
- C.20 inductors in series
- D.20 inductors in parallel
Show answer
Answer: A. 15 inductors in parallel — Equal inductors in parallel combine like resistors: L/n = 15/15 = 1 H.
- Q3 · ECAT Past Paper 04 · Electromagnetic Induction
The current through a 2 mH inductor is i = 2 sin(100t) A. The voltage across the inductor will be:
- A.400 mV
- B.4 cos(100t) mV
- C.400 cos(100t) mV
- D.4 sin(100t) mV
Show answer
Answer: C. 400 cos(100t) mV — V = L di/dt = 2 × 10⁻³ × 200 cos(100t) = 0.4 cos(100t) V = 400 cos(100t) mV.