Paper 4 Electric Fields Drills

Q1 Potential Gradient Between Parallel Plates

A student investigates the electric field in the central region between two large parallel conducting plates. A high-resistance voltmeter measures the potential $V$ at positions $x$ along a line perpendicular to the plates. The results are shown below.

$x$/cm	0.0	1.0	2.0	3.0	4.0	5.0	6.0
$V$/V	0.0	2.1	4.1	6.0	8.1	10.0	12.1

1. Plot a graph of $V$ against $x$ and draw a best-fit straight line. [5]
2. Use your graph to determine the magnitude of the electric field strength between the plates. State the SI unit. [3]
3. Explain what feature of the graph indicates that the field is approximately uniform. [2]
4. Explain why the student takes measurements in the central region rather than close to the plate edges. [2]

Q2 Measuring Plate Field

A pair of parallel plates is connected to a variable high-voltage supply. Plate separation is measured with vernier calipers.

1. State the measurements needed to determine $E$ between the plates. [2]
2. Explain one safety precaution. [1]
3. Explain why the field near the edges differs from the field in the central region. [2]