IB Physics HL C.3.9 Young Double-Slit Equation Question Bank

Practise IB Physics HL C.3.9 by solving Young double-slit equation problems with fringe spacing, angular separation and changing geometry.

[Maximum number: 1]

A student investigates how light can be used to measure the speed of a toy train.

Figure for Question C.3.9—Young double-slit equation question 1 — IB Physics HL

Light from a laser is incident on a double slit. The light from the slits is detected by a light sensor attached to the train.

The graph shows the variation with time of the output voltage from the light sensor as the train moves parallel to the slits. The output voltage is proportional to the intensity of light incident on the sensor.

The slits are separated by 1.5 mm and the laser light has a wavelength of $6.3 \times 10^{-7} \mathrm{~m}$ . The slits are 5.0 m from the train track. Calculate the separation between two adjacent positions of the train when the output voltage is at a maximum.

« $s=\frac{\lambda D}{d}=\frac{6.3 \times 10^{-7} \times 5.0}{1.5 \times 10^{-3}}=$ » $2.1 \times 10^{-3}$ « m »

If no unit assume m.

Correct answer only.

All question bank results loaded

C.3.9—Young double-slit equation question 1