A student carries out an experiment to determine the resistance per unit length of a wire $Y$ . They measure the potential difference $V$ across wire $Y$ for several different currents $I$ . The results are shown in the table below:

$\text{A}$	$\text{V}$
0.30	0.45
0.40	0.60
0.50	0.75
0.60	0.90
0.70	1.05

The measured length of wire $Y$ is $25.0\text{ cm}$ .

Determine the gradient $G$ of the graph of $V$ against $I$ .

Calculate the resistance per unit length $R$ of wire $Y$ using the equation:

\frac{G}{l}

Give your value for $R$ to a suitable number of significant figures and include the unit.

The student discovers that the resistance wire in the circuit control loop becomes very hot when the adjustable contact is connected to short lengths of the wire. Suggest one practical improvement that would help to reduce this effect.

$\text{A}$	$\text{V}$
0.30	0.45
0.40	0.60
0.50	0.75
0.60	0.90
0.70	1.05

The measured length of wire $Y$ is $25.0\text{ cm}$ .

Determine the gradient $G$ of the graph of $V$ against $I$ .

Calculate the resistance per unit length $R$ of wire $Y$ using the equation:

\frac{G}{l}

Give your value for $R$ to a suitable number of significant figures and include the unit.

4.2.4a Resistance

Question 26

Markscheme

4.2.4a Resistance

Question 26

Markscheme

4.2.4a Resistance

Question 26

4.2.4a Resistance Questions

4.2.4a Resistance

Question 26

4.2.4a Resistance Questions