Physics 9702/52 — February/March 2020

Fig. 1.1 shows a bar magnet attached to a spring.

The bar magnet is displaced a distance $x$ from its equilibrium position and released. It then oscillates vertically.

A student investigates how the maximum induced electromotive force (e.m.f.) $E$ in a coil placed below the magnet depends on $x$.

It is suggested that the relationship between $E$ and $x$ is

where $B$ is the magnetic flux density at one of the poles of the bar magnet, $N$ is the number of turns on the coil, $k$ is the spring constant, $m$ is the mass of the magnet and $\alpha$ is a constant.

Design a laboratory experiment to test the relationship between $E$ and $x$.
Explain how your results could be used to determine a value for $\alpha$.

You should draw a diagram, on page 3, showing the arrangement of your equipment. In your account you should pay particular attention to:

• the procedure to be followed
• the measurements to be taken
• the control of variables
• the analysis of the data
• any safety precautions to be taken.