Electricity & Circuits Quiz

1. What is electric current?

1. The energy stored in a battery
2. The flow of electric charge (electrons) through a conductor
3. The resistance of a wire
4. The voltage across a component

2. What is the SI unit of electrical resistance?

1. Ampere (A)
2. Ohm (Ω)
3. Volt (V)
4. Watt (W)

3. State Ohm's Law.

1. I = V + R
2. P = I × V
3. R = V + I
4. V = I × R

4. A circuit has a voltage of 12 V and a resistance of 4 Ω. What is the current?

1. 0.33 A
2. 3 A
3. 48 A
4. 8 A

5. In a series circuit with two resistors, how does the total resistance compare to the individual resistors?

1. Total resistance equals the larger resistor only
2. Total resistance is less than either individual resistor
3. Total resistance is the product of all resistors
4. Total resistance is the sum of all resistors

6. In a parallel circuit with two identical resistors of 10 Ω each, what is the total resistance?

1. 10 Ω
2. 2.5 Ω
3. 20 Ω
4. 5 Ω

7. What does a voltmeter measure and how is it connected?

1. Current; connected in series
2. Power; connected in series
3. Resistance; connected anywhere
4. Voltage; connected in parallel across a component

8. What is the formula for electrical power?

1. P = I²/R
2. P = V × I
3. P = V/I
4. P = V² × I

9. What is the difference between AC and DC electricity?

1. AC flows in one direction; DC alternates direction
2. AC is used in batteries; DC is used in homes
3. DC flows in one direction; AC periodically reverses direction
4. There is no practical difference

10. What is potential difference (voltage)?

1. The energy transferred per unit charge between two points
2. The number of electrons in a wire
3. The speed of electrons in a conductor
4. The total resistance in a circuit

11. A 1200 W kettle is used for 0.1 hours. How many kilowatt-hours of energy does it use?

1. 0.12 kWh
2. 1.2 kWh
3. 12 kWh
4. 120 kWh

12. What is an LED?

1. A device that converts light into electricity
2. A device that stores electrical charge
3. A Light Emitting Diode — a semiconductor component that emits light when current flows through it
4. A type of resistor

13. In a series circuit, if one bulb blows, what happens to the other bulbs?

1. They all go out
2. They flicker
3. They glow brighter
4. They stay the same

14. What is the charge on an electron?

1. Negative
2. Neutral
3. Positive
4. Variable

15. What is a superconductor?

1. A conductor that resists very high currents
2. A material that conducts electricity with zero resistance below a critical temperature
3. A very good conductor like copper
4. An insulator at low temperatures

16. What is the function of a fuse in an electrical circuit?

1. To increase voltage
2. To melt and break the circuit if current is too high, preventing fire or damage
3. To reduce resistance
4. To store charge

17. Two resistors of 6 Ω and 3 Ω are connected in parallel. What is the total resistance?

1. 18 Ω
2. 2 Ω
3. 4.5 Ω
4. 9 Ω

18. What is the relationship between charge (Q), current (I), and time (t)?

1. I = Q × t
2. Q = I × t
3. Q = I/t
4. t = Q × I

19. Which material is the best electrical conductor?

1. Glass
2. Plastic
3. Rubber
4. Silver

20. What is the National Grid?

1. A network of gas pipelines
2. A system of pylons, cables, and transformers that distributes electricity from power stations to homes and businesses
3. A type of solar power grid
4. The UK's broadband network