Physics 5054/32 — October/November 2021

Fig. 1.1 is on page 3 of your question paper.

Measure and record angle $a$ on Fig. 1.1.

angle $a$ = ______ $^\circ$

On Fig. 1.1:

• place the illuminated slit plate or the slit plate of the ray box on the line PP. If you are using the small lamp with the slit plate, you will need to turn the lamp upside down so that the glass is touching the paper next to the slit. Adjust the position of the slit plate so that, when the lamp or ray box is switched on, a single ray of light emerging from the slit lines up with the centre line marked on Fig. 1.1
• place the pair of mirrors so that the corner where they are joined together is at point C and one mirror lines up with the marked area, as shown on Fig. 1.1. A small amount of adhesive putty may be used to fix the mirror in place. This mirror is mirror 1.

Switch on the lamp.

Observe the ray reflected from mirror 1. Without moving mirror 1, adjust the position of mirror 2 so that the ray also reflects from this mirror to cross the centre line between X and the slit.

The distance from X to the point where the reflected ray crosses the centre line is $d$.

Describe how you could investigate the relationship between angle $a$ and the distance $d$.

On Fig. 1.2, sketch a graph of the relationship between the angle $a$ and distance $d$.