Physics 5054 · O Level · Electric circuits

Electric circuits — practice question

In a laboratory at room temperature, a student assembles the circuit shown in Fig. 10.1. The battery has an electromotive force (e.m.f.) of 12 V, and the switch is then closed.
(a)[2]

The circuit’s connecting wires are copper with insulating plastic around them. Name the particles that travel in the copper and state the direction of their movement at point Y in the circuit.

(b(i))[1]

At room temperature, component Z has a resistance of $6.0\,\Omega$. Name component Z.

(b(ii))[3]

Calculate the resistance of the complete circuit.

(b(iii))[2]

Calculate the current shown by the ammeter.

(b(iv))[1]

Here, the current in the ammeter is $I_A$, the current in the $1.5\,\Omega$ resistor is $I_R$ and the current in component Z is $I_Z$. Write an equation linking $I_A$, $I_R$ and $I_Z$.

(c)[4]

Before the switch is closed, the trace is a horizontal line through the middle of the screen, as shown in Fig. 10.2. Once the switch is closed, the trace stays horizontal but shifts up the screen. Component Z is heated. State and explain what is observed on the oscilloscope screen as the temperature of Z rises.

(d(i))[1]

The 12 V battery is built from cells with electromotive force (e.m.f.) $1.5\,\text{V}$, all connected in series. Calculate how many $1.5\,\text{V}$ cells are needed to make the battery.

(d(ii))[1]

State the e.m.f. of a battery formed by connecting all of these cells in parallel.

Worked solution & mark scheme

This 15-mark question has a full step-by-step worked solution and mark scheme. One marking point: Electrons act as charge carriers

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