A screen is placed from a single slit

PHYSICS · Subjective · A Level · Physics · Waves · Waves

Problem

A screen is placed

50\,\text{cm}

from a single slit, which is illuminated with light of wavelength

6000\,\text{Å}

. If the distance between the first and third minima in the diffraction pattern is

3.0\,\text{mm}

, what is the width of the slit?