Sec. 2 Science - Revision of Electricity

Two identical resistors are connected to a 15 V cell as shown in the circuit above. Which of the following correctly describes the readings on the ammeters A₁ and A₂ when switch K is closed?

• A) A₂ has the same reading as A₁.

• B) A₂ has half the reading as A₁.

• C) A₂ has double the reading of A₁.

• D) A₁ has a zero reading while A₂ has a non-zero reading.

2. The diagram shows part of an electric circuit.

What is the reading on the ammeter?

• A) 6.0 A

• B) 3.0 A

• C) 1.5 A

• D) 0.75 A

The following diagrams show two lamps, a switch and a battery connected in a circuit. Which one of the circuits is not equivalent to the other three circuits?

• A) Option A.

• B) Option B.

• C) Option C.

• D) Option D.

A voltmeter and an ammeter are used to measure the resistance of a resistor. Which diagram shows the voltmeter and the ammeter correctly connected?

• A) Option A.

• B) Option B.

• C) Option C.

• D) Option D.

The diagram shows three identical resistors, three ammeters and a battery, connected in a circuit. What is the order of the magnitudes of the readings on the ammeters from smallest to largest?

• A) ammeter 1 < ammeter 2 < ammeter 3

• B) ammeter 1 < ammeter 3 < ammeter 2

• C) ammeter 2 < ammeter 3 < ammeter 1

• D) ammeter 3 < ammeter 2 < ammeter 1

The diagram shows a cell connected to three resistors, R1, R2 and R3. A student connects an ammeter first in position 1, then in position 2, 3 and 4 in turn. In which position(s) does the ammeter show the current in R1?

• A) 1, 2 and 4.

• B) 1 and 2 only.

• C) 3 only.

• D) 4 only.

A student sets up a circuit which she calls circuit 1. She records the value of the current I₁, and calculates the resistance R₁ of the circuit. She then connects an identical resistor in parallel with the original resistor. She calls this circuit 2. She records current I₂ and calculates the total resistance R₂ of this circuit. Which row correctly compares the two currents and the two resistances in the circuits?

• A) I₂ is greater than I₁ and R₂ is greater than R₁.

• B) I₂ is greater than I₁ and R₂ is less than R₁.

• C) I₂ is less than I₁ and R₂ is greater than R₁.

• D) I₂ is less than I₁ and R₂ is less than R₁.

The diagram shows a circuit including a lamp, an electric bell and three switches S₁, S₂ and S₃. The lamp and bell are not faulty. The bell is ringing but the lamp is not lit. Which switches are closed?

• A) S₁ only.

• B) S₁ and S₂ only.

• C) S₁ and S₃ only.

• D) S₁, S₂ and S₃.

A student is designing a lighting circuit for a dolls’ house. She sets up two different circuits. Each circuit contains a 12 V power supply and three identical lamps. Each lamp is designed to operate at normal brightness when connected individually to a 12 V supply. Which statement is correct?

• A) In circuit 1, each of the lamps is at normal brightness.

• B) In circuit 1, if one lamp fails, the other lamps remain lit.

• C) In circuit 2, if one lamp fails, the other lamps remain lit.

• D) In circuit 2, the current from the power supply is less than in circuit 1.

A student uses the circuit shown to determine the resistance of two identical resistors. The voltmeter reading is 2.2 V and the ammeter reading is 0.25 A. What is the resistance of each resistor?

• A) 0.275 Ω

• B) 0.55 Ω

• C) 4.4 Ω

• D) 8.8 Ω