Question

Relation between dispersive power and order of spectrum

Answer 1

Answer:

(a + b) cos θ dθ = n dλ

In equation (ii) dθ/dλ is the dispersive power, n is the order of the spectrum, N' is the number of lines per cm of the grating surface and θ is the angle of diffraction for the n th order principal maximum of wavelength λ.