Physics 9702/53 — October/November 2012

Two identical light sources are viewed from a distance, as shown in Fig 1.1. When the angle $\theta$ between the light sources is large, they are seen as separate.

The sources are moved closer together. At a particular angle $\theta_1$ the two sources appear as a single source.

It is suggested that $\theta_1$ is directly proportional to the wavelength $\lambda$ of the light from the sources.

Design a laboratory experiment using two light sources to test the relationship between $\theta_1$ and $\lambda$. You should draw a diagram, on page 3, showing the arrangement of your equipment. In your account you should pay particular attention to

(a) the procedure to be followed,
(b) the measurements to be taken,
(c) the control of variables,
(d) the analysis of the data,
(e) the safety precautions to be taken.