Question

The resolving power of a spectrometer consisting of a collimator, a grating and a telescope can be increased by
1. increasing the angular magnification of the telescope
2. increasing the period of the grating
3. decreasing the period of the grating
4. decreasing the slit-width of the collimator

Answer 1

Correct Answer - Option 3 : decreasing the period of the grating

The resolving power of grating spectrometer is the measure of the smallest wavelength difference that can be resolved in a spectrum

Number of grooves per mm of a grating device is the way to quantity resolution

When groove density is higher it means higher optical resolution.

Thus, the grove density is improved by decreasing the period of grating and this improves its Resolution.