Electromagnetic Induction MCQs
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Mutual inductance can also be defined as:
- A. M = N2 dΦ/dt
- B. M = N2 dt/di
- C. M = N2 di/dt
- D. M = N2 dt/dΦ
- Correct Answer: Option A
The time constant is the time it takes the current in an inductive circuit to rise to
- A. 66% of its final steady state value
- B. 70% of its final steady state value
- C. 63% of its final steady state value
- D. 50% of its final steady state value
- Correct Answer: Option C
The time constant of an inductive circuit is defined as the ratio of
- A. R/L
- B. Rt/L
- C. Lt/R
- D. L/R
- Correct Answer: Option D
The growth of current in an inductive circuit follows
- A. hyperbolic law
- B. Ohm's law
- C. exponential law
- D. linear law
- Correct Answer: Option C
Air gap in the iron core of an inductor prevents
- A. hyteresis loss
- B. flux change
- C. transformer action
- D. core saturation
- Correct Answer: Option D
When steel toroidal ring is magnetized by passing current through its coil, it develops no magnetic poles
- A. True
- B. False
- C. Partly true
- D. Partly false
- Correct Answer: Option A
The flux linked with a coil of inductance L carrying current i is d/dt (Li)
- A. True
- B. False
- C. Partly true
- D. Partly false
- Correct Answer: Option B
Sparking occurs when a load is switched off because the circuit has high
- A. capacitance
- B. inductance
- C. resistance
- D. impedance
- Correct Answer: Option B
According to Lenz’ law the direction of induced e.m.f. and hence current
- A. may be found by the right hand rule
- B. always opposes the cause producing it
- C. is determined by the rate of cutting flux
- D. may be found by the left hand rule
- Correct Answer: Option B
The law that induces emf and current always opposes the cause producing them was discovered by
- A. Lenz
- B. Faraday
- C. Maxwell
- D. Ohm
- Correct Answer: Option A