Practice Test: Question Set - 03
1. The law that the induced e.m.f. and current always oppose the cause producing them is due to
- (A) Faraday
- (B) Lenz
- (C) Newton
- (D) Coulomb
2. An open coil has
- (A) Zero resistance and inductance
- (B) Infinite resistance and zero inductance
- (C) Infinite resistance and normal inductance
- (D) Zero resistance and high inductance
3. Find the force acting on a conductor 3m long carrying a current of 50 amperes at right angles to a magnetic field having a flux density of 0.67 tesla
- (A) 100 N
- (B) 400 N
- (C) 600 N
- (D) 1000 N
4. If current in a conductor increases then according to Lenz's law self-induced voltage will
- (A) Aid the increasing current
- (B) Tend to decrease the amount of current
- (C) Produce current opposite to the increasing current
- (D) Aid the applied voltage
5. As per Faraday's laws of electromagnetic induction, an e.m.f. is induced in a conductor whenever it
- (A) Lies perpendicular to the magnetic flux
- (B) Lies in a magnetic field
- (C) Cuts magnetic flux
- (D) Moves parallel to the direction of the
magnetic field
6. An e.m.f. of 16 volts is induced in a coil of inductance 4H. The rate of change of current must be
- (A) 64 A/s
- (B) 32 A/s
- (C) 16 A/s
- (D) 4 A/s
7. A 500 turns solenoid develops an average induced voltage of 60 V. Over what time interval must a flux change of 0.06 Wb occur to produce such a voltage?
- (A) 0.01 s
- (B) 0.1 s
- (C) 0.5 s
- (D) 5 s
8. The self-inductance of the coil may be defined as equal to the e.m.f. induced in volts when the current in the circuit changes at the rate of unit Weber turns.
- (A) Yes
- (B) No
9. A coil induces 350 mV when the current changes at the rate of 1 A/s. The value of inductance is
- (A) 3500 mH
- (B) 350 mH
- (C) 250 mH
- (D) 150 mH
10. A coil with negligible resistance has 50V across it with 10 mA. The inductive reactance is
- (A) 50 ohms
- (B) 500 ohms
- (C) 1000 ohms
- (D) 5000 ohms
Blogger Comment
Facebook Comment