D.C. circuits MCQ with Answer

1. What is the unit of electric current?
   A. Volt
   B. Watt
   C. Ampere
   D. Ohm
   Answer: C

2. What is the unit of electric potential?
   A. Ampere
   B. Watt
   C. Ohm
   D. Volt
   Answer: D

3. What is the unit of resistance?
   A. Ampere
   B. Watt
   C. Volt
   D. Ohm
   Answer: D

4. What is Kirchhoff's first law?
   A. The total voltage in a closed circuit is equal to the sum of the voltage drops.
   B. The total current in a closed circuit is equal to the sum of the currents flowing into it.
   C. The resistance of a conductor is directly proportional to its length and inversely proportional to its cross-sectional area.
   D. The voltage across a resistance is directly proportional to the current flowing through it.
   Answer: B

5. What is Kirchhoff's second law?
   A. The total voltage in a closed circuit is equal to the sum of the voltage drops.
   B. The total current in a closed circuit is equal to the sum of the currents flowing into it.
   C. The resistance of a conductor is directly proportional to its length and inversely proportional to its cross-sectional area.
   D. The algebraic sum of the voltage drops around any closed loop in a circuit is equal to zero.
   Answer: D

6. What is the formula for calculating electric power?
   A. P = VI
   B. P = V/R
   C. P = I^2R
   D. All of the above
   Answer: D

7. What is the difference between a series circuit and a parallel circuit?
   A. A series circuit has one path for the current, while a parallel circuit has multiple paths.
   B. A series circuit has multiple paths for the current, while a parallel circuit has one path.
   C. A series circuit has more resistance than a parallel circuit.
   D. A parallel circuit has more resistance than a series circuit.
   Answer: A

8. What is the equivalent resistance of two resistors in series with values of 10 ohms and 20 ohms?
   A. 5 ohms
   B. 15 ohms
   C. 30 ohms
   D. 50 ohms
   Answer: B

9. What is the equivalent resistance of two resistors in parallel with values of 10 ohms and 20 ohms?
   A. 5 ohms
   B. 15 ohms
   C. 30 ohms
   D. 50 ohms
   Answer: C

10. What is the voltage across a 5-ohm resistor when a current of 2 amperes flows through it?
    A. 0.4 volts
    B. 2.5 volts
    C. 5 volts
    D. 10 volts
    Answer: C

11. What is the current through a 10-ohm resistor when a voltage of 20 volts is applied across it?
    A. 0.2 amperes
    B. 2 amperes
    C. 10 amperes
    D. 20 amperes
    Answer: B

12. What is the resistance of a circuit if a current of 4 amperes flows through it when a voltage of 12 volts is applied?
    A. 3 ohms
    B. 4 ohms
    C. 8 ohms
    D. 16 ohms
    Answer: A

13. What is the voltage drop across a 50-ohm resistor when a current of 2 amperes flows through it?
    A. 50 volts
    B. 100 volts
    C. 200 volts
    D. 400 volts
    Answer: A

14. What is the total resistance of three 10-ohm resistors in parallel?
    A. 10/3 ohms
    B. 30/2 ohms
    C. 30 ohms
    D. 10 ohms
    Answer: A

15. What is the total resistance of two 20-ohm resistors in series?
    A. 20 ohms
    B. 40 ohms
    C. 10 ohms
    D. 2 ohms
    Answer: B

16. What is the total current in a circuit with two 10-ohm resistors in parallel and a 20-volt battery?
    A. 2 amperes
    B. 4 amperes
    C. 6 amperes
    D. 8 amperes
    Answer: B

17. What is the total voltage in a circuit with two 20-ohm resistors in series and a 2-ampere current?
    A. 10 volts
    B. 20 volts
    C. 40 volts
    D. 80 volts
    Answer: C

18. What is the resistance of a circuit with a 12-volt battery and a current of 3 amperes?
    A. 4 ohms
    B. 6 ohms
    C. 9 ohms
    D. 36 ohms
    Answer: B

19. What is the power dissipated in a 10-ohm resistor with a current of 2 amperes flowing through it?
    A. 4 watts
    B. 20 watts
    C. 40 watts
    D. 100 watts
    Answer: C