Electrical Engineering Quiz
Questions: 16 · 10 minutes
1. Three resistors are connected in series to a DC source. Which quantity is the same through every resistor?
Voltage drop
Power dissipation
Current
Resistance
2. A device draws 2 A from a 230 V supply at unity power factor. Approximately how much real power does it consume?
460 W
232 W
920 W
115 W
3. A temporary overcurrent trips a correctly selected circuit breaker, and inspection finds no continuing fault. What feature distinguishes the breaker from a conventional fuse?
The breaker limits current without ever opening the circuit
The breaker can normally be reset, while a blown fuse element must be replaced
The breaker responds only to voltage, while a fuse responds only to current
The breaker is intended to increase the circuit's normal operating current
4. A two-input NAND gate receives logic 1 at both inputs. What output does it produce?
Logic 1, because either input is high
An undefined state
A toggling output
Logic 0
5. A 10 kΩ resistor and a 100 μF capacitor form an RC circuit. What is the time constant?
1 s
0.1 s
0.01 s
10 s
6. Compared with a similar single-phase supply, what is a major engineering advantage of a balanced three-phase system?
It eliminates the need for insulation
It always operates at a lower voltage
It can deliver nearly constant total power and produce a naturally rotating magnetic field
It prevents all reactive power
7. After a capacitor has been connected to a constant DC source for a long time and reached steady state, how does it ideally behave in that circuit?
As an open circuit
As a constant-current source
As a short circuit
As an inductor
8. A 6 Ω resistor and a 3 Ω resistor are connected in parallel. What is their equivalent resistance?
9 Ω
4.5 Ω
3 Ω
2 Ω
9. A 12 V source is connected across a 6 Ω resistor. Assuming an ideal source and resistor, what current flows?
72 A
0.5 A
6 A
2 A
10. An ideal transformer has a primary-to-secondary turns ratio of 10:1. If 230 V RMS is applied to the primary, what is the secondary voltage?
23 V RMS
2.3 V RMS
230 V RMS
2300 V RMS
11. An ideal inductor carries a steady current just before a switch changes position. What must be true at the switching instant?
Its voltage must remain zero
Its current must immediately become zero
Its resistance must become infinite
Its current cannot change instantaneously
12. A sinusoidal voltage has a peak value of approximately 325 V. What is its RMS value?
163 V
325 V
230 V
460 V
13. For a standard silicon diode to conduct appreciably in its forward direction, which condition is required?
The cathode must be at a higher potential than the anode by roughly the forward voltage
The anode must be at a higher potential than the cathode by roughly the forward voltage
The anode and cathode must always be at exactly the same potential
The diode must be driven beyond its reverse breakdown voltage
14. At a circuit node, currents of 5 A and 2 A enter. One branch carries 4 A away. According to Kirchhoff's current law, what current leaves through the remaining branch?
7 A
3 A
1 A
11 A
15. An ideal inverting operational-amplifier circuit uses a 10 kΩ input resistor and a 100 kΩ feedback resistor. What is its closed-loop voltage gain?
A non-inverting gain of 10 V/V
An inverting gain of 10 V/V, equivalent to −10
An inverting gain of 0.1 V/V, equivalent to −0.1
A non-inverting gain of 0.1 V/V
16. Why does the rotor of a typical induction motor run slightly below synchronous speed while supplying mechanical load?
The supply frequency falls whenever load is applied
The stator magnetic field slows to match the rotor
A speed difference is needed to induce rotor current and produce torque
The rotor must remain stationary relative to the rotating field