1. In a DC circuit, the current flows in:
A. One direction only
B. Alternating directions
C. Both directions simultaneously
D. A non-linear direction
Answer: A. One direction only
2. In a simple DC circuit consisting of a 12V battery and a resistor of 6Ω, the current flowing through the circuit is:
A. 0.5 A
B. 1 A
C. 2 A
D. 12 A
Answer: C. 2 A
3. Which of the following is true for a DC circuit?
A. The voltage varies sinusoidally with time
B. The current remains constant over time
C. The current alternates direction periodically
D. The voltage is only constant at certain points
Answer: B. The current remains constant over time
4. The power dissipated in a resistor in a DC circuit is given by the formula:
A. P=IVP = IV
B. P=I2RP = I^2R
C. P=V2RP = \frac{V^2}{R}
D. All of the above
Answer: D. All of the above
5. In a DC circuit, if the voltage is doubled, the current will:
A. Remain the same
B. Double
C. Halve
D. Increase four times
Answer: B. Double
6. In an AC circuit, the current varies:
A. Constantly in one direction
B. Sinusoidally over time
C. Steadily over time
D. In a linear fashion
Answer: B. Sinusoidally over time
7. The voltage in an AC circuit typically varies in a pattern known as:
A. Square wave
B. Triangular wave
C. Sinusoidal wave
D. Sawtooth wave
Answer: C. Sinusoidal wave
8. The RMS (Root Mean Square) value of an AC voltage is equivalent to:
A. The peak voltage
B. The average voltage
C. The DC voltage that produces the same power
D. The maximum instantaneous voltage
Answer: C. The DC voltage that produces the same power
9. Which of the following is the primary characteristic that differentiates an AC circuit from a DC circuit?
A. The direction of current flow
B. The resistance of the circuit
C. The source of power
D. The presence of inductance
Answer: A. The direction of current flow
10. In an AC circuit, the current and voltage are generally out of phase by 90° in which type of component?
A. Resistor
B. Inductor
C. Capacitor
D. Transformer
Answer: B. Inductor
11. The frequency of an AC supply is the number of cycles per:
A. Minute
B. Second
C. Hour
D. Day
Answer: B. Second
12. In a purely resistive AC circuit, the current and voltage are:
A. 180° out of phase
B. 90° out of phase
C. In phase
D. Completely unrelated
Answer: C. In phase
13. In an AC circuit, what is the term for the maximum voltage or current reached in one cycle?
A. RMS value
B. Peak value
C. Average value
D. Instantaneous value
Answer: B. Peak value
14. The power factor in an AC circuit is the ratio of:
A. Voltage to current
B. Real power to apparent power
C. Current to resistance
D. Voltage to resistance
Answer: B. Real power to apparent power
15. The primary advantage of using AC over DC for power transmission is:
A. AC can be easily transformed to different voltages
B. DC is easier to generate
C. DC circuits are more efficient
D. AC is cheaper to generate
Answer: A. AC can be easily transformed to different voltages
16. In a DC circuit, the power remains constant, whereas in an AC circuit, the power can:
A. Only increase
B. Vary over time
C. Only decrease
D. Stay the same
Answer: B. Vary over time
17. The average value of a sinusoidal AC voltage is:
A. Equal to the RMS value
B. Equal to the peak value
C. Zero
D. Half of the peak value
Answer: C. Zero
18. Which of the following components is most commonly used to convert AC to DC in a circuit?
A. Resistor
B. Diode
C. Capacitor
D. Inductor
Answer: B. Diode
19. In a simple AC circuit with a resistor, the relationship between voltage and current is:
A. V=IRV = IR
B. V=I2RV = I^2R
C. P=IVP = IV
D. P=I2RP = I^2R
Answer: A. V=IRV = IR
20. In a series AC circuit containing a resistor, inductor, and capacitor, the impedance is:
A. Equal to the sum of the resistances
B. The square root of the sum of the squares of the individual impedances
C. Zero
D. Equal to the maximum voltage
Answer: B. The square root of the sum of the squares of the individual impedances