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This section includes 36 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering knowledge and support exam preparation. Choose a topic below to get started.
1. |
A 240 H inductor is equivalent to a |
A. | 0.240 mH inductor |
B. | 0.000240 mH inductor |
C. | 240 mH inductor |
D. | 240 H inductor |
Answer» B. 0.000240 mH inductor | |
2. |
The voltage across a coil when = 20 mA/s and = 8 H is |
A. | 16 mV |
B. | 160 mV |
C. | 1.6 mV |
D. | 2.5 mV |
Answer» C. 1.6 mV | |
3. |
An inductance of 0.08 H is larger than |
A. | 0.0000008 H |
B. | 0.000000008 H |
C. | 0.000008 H |
D. | 0.00008 mH |
Answer» C. 0.000008 H | |
4. |
Two inductors, and , are in parallel. has a value of 25 H and a value of 50 H. The parallel combination is in series with , a 20 H coil. The entire combination is across an ac source of 60 V at 300 kHz. The total rms current is |
A. | 87 mA |
B. | 870 mA |
C. | 87 A |
D. | 337 mA |
Answer» C. 87 A | |
5. |
An inductor, a 1 k resistor, and a switch are connected in series across a 6 V battery. At the instant the switch is closed, the inductor voltage is |
A. | 0 V |
B. | 6 V |
C. | 12 V |
D. | 4 V |
Answer» C. 12 V | |
6. |
An 18 V power supply is connected across a coil with a winding resistance of 180 . Current flow in the coil is |
A. | 1 mA |
B. | 10 mA |
C. | 100 mA |
D. | 1 A |
Answer» D. 1 A | |
7. |
A switch, a 220 resistor, and a 60 mH inductor are in series across a 20 V battery. What is the current through the inductor two time constants after the switch is closed? |
A. | 91 mA |
B. | 78 mA |
C. | 57 mA |
D. | 400 mA |
Answer» C. 57 mA | |
8. |
A 320 H coil is in series with a 3.3 k 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 |
D. | s |
E. | 48 s |
Answer» D. s | |
9. |
Five inductors are connected in series. The lowest value is 8 μH. If the value of each inductor is twice that of the preceding one, and if the inductors are connected in order of ascending values, the total inductance is |
A. | 8 H |
B. | 32 μH |
C. | 64 μH |
D. | 248 μH |
Answer» E. | |
10. |
is directly proportional to frequency and inductance. |
A. | True |
B. | False |
Answer» B. False | |
11. |
An induced voltage is produced as a result of a dc voltage. |
A. | True |
B. | False |
Answer» C. | |
12. |
Inductance is the property of an inductor that produces an opposition to any change in current. |
A. | True |
B. | False |
Answer» B. False | |
13. |
Inductance is indirectly proportional to the square of the number of turns, the permeability, and the cross-sectional area of the core. |
A. | True |
B. | False |
Answer» C. | |
14. |
Inductors add in parallel. |
A. | True |
B. | False |
Answer» C. | |
15. |
Energy is stored by an inductor in an electrostatic field. |
A. | True |
B. | False |
Answer» C. | |
16. |
The term is more commonly used in connection with an inductor used to block off high frequencies. |
A. | True |
B. | False |
Answer» B. False | |
17. |
All coil cores are made of iron. |
A. | True |
B. | False |
Answer» C. | |
18. |
Two 10 H inductors are in parallel and the parallel combination is in series with a third 10 H inductor. What is the approximate total reactance when a voltage with a frequency of 7 kHz is applied across the circuit terminals? |
A. | 219 k |
B. | 66 k |
C. | 660 k |
D. | 1.3 M |
Answer» D. 1.3 M | |
19. |
When the current through an inductor is cut in half, the amount of energy stored in the electromagnetic field |
A. | is quartered |
B. | quadruples |
C. | doubles |
D. | does not change |
Answer» B. quadruples | |
20. |
An inductance of 0.43 mH is smaller than |
A. | 43 H |
B. | 430 H |
C. | 0.05 H |
D. | 0.00043 H |
Answer» D. 0.00043 H | |
21. |
The following coils are in parallel: 75 H, 40 H, 25 H, and 15 H. The total inductance is approximately |
A. | 6.9 H |
B. | 14 H |
C. | 2.2 H |
D. | 155 H |
Answer» B. 14 H | |
22. |
An inductor and a resistor are in series with a sine wave voltage source. The frequency is set so that the inductive reactance is equal to the resistance. If the frequency is increased, then |
A. | VR ‚â• VL |
B. | VL < VR |
C. | VL = VR |
D. | VL > VR |
Answer» E. | |
23. |
When the current through an inductor decreases, the amount of energy stored in the electromagnetic field |
A. | increases |
B. | decreases |
C. | remains the same |
D. | doubles |
Answer» C. remains the same | |
24. |
Faraday's law states that relative motion between a magnetic field and a coil induces a voltage across the coil. |
A. | 1 |
B. | |
Answer» B. | |
25. |
Five inductors are connected in series. The lowest value is 8 μH. If the value of each inductor is twice that of the preceding one, and if the inductors are connected in order of ascending values, the total inductance is |
A. | 8 H |
B. | 32 μH |
C. | 64 μH |
D. | 248 μH |
Answer» E. | |
26. |
A switch, a 220 resistor, and a 60 mH inductor are in series across a 20 V battery. What is the current through the inductor two time constants after the switch is closed? |
A. | 91 mA |
B. | 78 mA |
C. | 57 mA |
D. | 400 mA |
Answer» C. 57 mA | |
27. |
The inductance of an iron-core coil decreases if |
A. | the number of turns is decreased |
B. | the iron core is removed |
C. | the length of the coil decreases |
D. | none of the above |
Answer» B. the iron core is removed | |
28. |
Three 15 mH inductors are in series. The total inductance is |
A. | 15 mH |
B. | 30 mH |
C. | 45 mH |
D. | 5 mH |
Answer» D. 5 mH | |
29. |
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 |
Answer» E. | |
30. |
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 |
Answer» E. | |
31. |
The voltage across a coil when di/dt = 20 mA/s and L = 8 H is |
A. | 16 mV |
B. | 160 mV |
C. | 1.6 mV |
D. | 2.5 mV |
Answer» C. 1.6 mV | |
32. |
The permeability of a core material is an indication of the ability of the material to establish a magnetic field. |
A. | 1 |
B. | |
C. | 1 |
D. | |
Answer» B. | |
33. |
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 |
Answer» E. | |
34. |
A sine wave voltage is applied across an inductor. When the frequency of the voltage is decreased, the current |
A. | is increased |
B. | is decreased |
C. | does not change |
D. | momentarily goes to zero |
Answer» B. is decreased | |
35. |
A 240 H inductor is equivalent to a |
A. | 0.240 mH inductor |
B. | 0.000240 mH inductor |
C. | 240 mH inductor |
D. | 240 H inductor |
Answer» B. 0.000240 mH inductor | |
36. |
An inductance of 0.08 H is larger than |
A. | 0.0000008 H |
B. | 0.000000008 H |
C. | 0.000008 H |
D. | 0.00008 mH |
Answer» C. 0.000008 H | |