DIFFRACTION GRATING - Q9

9) How does the angular dispersive power of the grating vary with (i) the order number n of the spectrum, (ii) the grating element or the number of lines per cm in the grating, and (iii) the wavelength λ?

Ans: 

Order number n of the spectrum:

Angular dispersive power of the grating is proportional to n.

Angular dispersive power increases with increase in n.

Grating element or the number of lines per cm in the grating:

Angular dispersive power of the grating is inversely proportional to the grating element.

Angular dispersive power of the grating is proportional to the number of lines per cm in the grating

Wavelength λ:

Angular dispersive power of the grating is independent of wavelength.