Physics 0625 · IGCSE · Electrical quantities

Electrical quantities — practice question

A student examines the resistance of a wire. Fig. 2.1 shows the circuit he uses. The circuit includes an ammeter A, a voltmeter V, resistance wire BC, a sliding contact S and a variable length d of wire.
(a)[1]

Record the ammeter reading shown in Fig. 2.2.

(b(i))[1]

Enter, in the last row of Table 2.1, the voltmeter reading shown in Fig. 2.3.

(b(ii))[1]

Calculate the resistance R of 100.0 cm of the resistance wire, using the equation $R = \frac{V}{I}$. Record R in the last row of Table 2.1.

(b(iii))[1]

Complete the column headings in Table 2.1.

(c)[4]

Plot a graph of resistance $R / \Omega$ (y-axis) against length $d / \text{cm}$ (x-axis). Draw a best-fit line.

(d)[3]

Use your graph to determine the resistance $R_{75}$ of a length $d = 75.0\,\text{cm}$ of the resistance wire. Show clearly on the graph how you obtained the value.

Worked solution & mark scheme

This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: 0.32

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI