AIM: TO MEASURE THE WAVELENGTH OF MONOCHROMATIC LIGHT.

The following values were obtained in an experiment to measure the wavelength of sodium light:

The diffraction grating used had 100 lines per mm.

Use these results to find a single value for the wavelength of sodium light.

Give a reason why the readings on the right are consistently smaller than the readings on the left.

SOLUTION

The angles on the right are slightly smaller than those on the left. This may be because the diffraction grating was not at right angles to the collimeter.