Test yourself

Boss quiz

11 questions on the whole topic. You get one try at each.

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  1. What is an electric current?

    • A kind of wire
    • A flow of charge
    • A kind of magnet
    • A flow of heat

  2. What is current measured in?

    • Volts (V)
    • Amperes (A)
    • Ohms (Ω)
    • Newtons (N)

  3. How is an ammeter connected?

    • Next to the circuit, not touching it
    • Across the two ends of the battery
    • In series, as part of the loop
    • In parallel, across a lamp

  4. In a series circuit, the current is…

    • biggest next to the battery
    • zero in the wires
    • smaller after each lamp
    • the same everywhere

  5. Two branches of a parallel circuit carry 0.2 A and 0.5 A. What is the total current from the battery?

    • 0.3 A
    • 0.7 A
    • 0.5 A
    • 0.2 A

  6. What is potential difference measured in?

    • Volts
    • Amps
    • Ohms
    • Joules

  7. How is a voltmeter connected?

    • Across a part, in parallel with it
    • Between two cells in a battery
    • In series, as part of the loop
    • It is not connected at all

  8. A lamp has 12 V across it and a current of 2 A through it. What is its resistance?

    • 14 Ω
    • 10 Ω
    • 24 Ω
    • 6 Ω

  9. Why is a copper wire coated in plastic?

    • Plastic is a conductor, so more current flows
    • Plastic is an insulator, so the current stays in the wire
    • Plastic makes the current bigger
    • Plastic stores the charge

  10. A balloon is rubbed on a jumper and gains electrons. What charge does the balloon have now?

    • Negative
    • Positive and negative equally
    • Positive
    • No charge

  11. Two objects both have a positive charge. What do they do?

    • Nothing at all
    • Repel each other
    • Attract each other
    • Lose their charge
Answers
  1. A flow of charge. In a wire, the charge is carried by electrons.
  2. Amperes (A). Amperes are often called amps.
  3. In series, as part of the loop. The current has to flow through the ammeter.
  4. the same everywhere. Current is not used up as it goes round.
  5. 0.7 A. The branch currents add: 0.2 A + 0.5 A = 0.7 A.
  6. Volts. Potential difference is also called voltage.
  7. Across a part, in parallel with it. It measures the potential difference between the two sides of the part.
  8. 6 Ω. resistance = potential difference ÷ current = 12 ÷ 2 = 6 Ω.
  9. Plastic is an insulator, so the current stays in the wire. The copper carries the current. The plastic keeps you safe.
  10. Negative. Electrons are negative, so gaining them makes an object negative.
  11. Repel each other. Like charges repel. Opposite charges attract.