Practice Test: Question Set - 03
1. A 2 mH, a 3.3 mH, and a 0.2 mH inductor are connected in series. The total inductance is
- (A) 55 mH
- (B) Less than
0.2 mH
- (C) Less than
5.5 mH
- (D) 5.5 mH
2. A 5 mH, a 4.3 mH, and a 0.6 mH inductor are connected in parallel. The total inductance is
- (A) 9.9 mH
- (B) Greater than
5 mH
- (C) 9.9 mH or
greater than 5 mH
- (D) Less than
0.6 mH
3. Inductors add in parallel.
- (A) True
- (B) False
4. Two inductors, L1 and L2, are in parallel. L1 has a value of 25 μH and L2 a value of 50 μH. The parallel combination is in series with L3, a 20 μH coil. The entire combination is across an ac source of 60 Vrms at 300 kHz. The total rms current is
- (A) 87 mA
- (B) 870 mA
- (C) 87 A
- (D) 337 mA
5. The winding resistance of a coil can be increased by
- (A) Increasing
the number of turns
- (B) Using a
thinner wire
- (C) Changing the
core material
- (D) Increasing
the number of turns or using thinner wire
6. All coil cores are made of iron.
- (A) True
- (B) False
7. The current through a 120 mH coil is changing at a rate of 150 mA/s. The voltage induced across the coil is
- (A) 1.8
mV
- (B) 18 mV
- (C) 180 mV
- (D) 1.25 mV
8. Three 15 mH inductors are in series. The total inductance is
- (A) 15 mH
- (B) 30
mH
- (C) 45 mH
- (D) 5 mH
9. Faraday's law states that relative motion between a magnetic field and a coil induces a voltage across the coil.
- (A) True
- (B) False
10. An 18 V power supply is connected across a coil with a winding resistance of 180 Ω. Current flow in the coil is
- (A) 1 mA
- (B) 10 mA
- (C) 100 mA
- (D) 1 A
11. A 320 μH coil is in series with a 3.3 kΩ resistor. How long does it take for current to build up to its full value?
- (A) 0.48 s
- (B) 0.48 ms
- (C) 0.48 μs
- (D) 48 s
12. XL is directly proportional to frequency and inductance.
- (A) True
- (B) False
13. The following coils are in parallel: 75 μH, 40 μH, 25 μH, and 15 μH. The total inductance is approximately
- (A) 6.9 μH
- (B) 14 μH
- (C) 2.2 μH
- (D) 155 μH
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