A diffraction pattern is produced on a screen from a single slit

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

Problem

A diffraction pattern is produced on a screen

1.8\,\text{m}

from a single slit. For light of wavelength

450\,\text{nm}

, the first dark fringe appears

6.0\,\text{mm}

from the centre of the pattern. Calculate the width of the slit.