Explain how the bright and dark interference fringes are produced.
The separation between the centres of bright fringe X and bright fringe Y in the pattern is $10.2\,\text{mm}$. The slit spacing is $1.2\,\text{mm}$. The slits are $3.1\,\text{m}$ from the screen. Calculate the wavelength of the light incident on the slits.
The light is replaced with other visible light that has a shorter wavelength. State how the new fringe separation will compare with the original fringe separation.
A stationary wave is set up on a stretched string AB, as shown in Fig. 6.2. On Fig. 6.2, draw a cross ($\times$) to show where a node is located.
State the phase difference for P and Q.
State the phase difference for P and R.
A stationary wave is set up on a stretched string AB, as shown in Fig. 6.2. P, Q and R are points on the string.