A parallel beam of light of wavelength 5900 Å falls normally on a plane transmission grating having 4250 lines/cm. Find the angle of diffraction for maximum intensity in first order.

Asked by Abhineet | 26th Nov, 2019, 02:03: AM

Expert Answer:

For transmission grating, d sinθ = n λ  ......................(1)
 
where d is distance between slits of grating, θ is angle of diffraction,
n is order of diffraction and λ is wavelngth of incident light .
 
d = 1/ N , where N is number of lines per unit length
 
we have , d = 1/N = 1/4250 cm   or  d = (1/4250)×10-2 m
 
Hence we get diffraction angle from eqn.(1),
 
(1/4250) × 10-2 sinθ = 5900  × 10-10
 
we get angle θ = 14.52°

Answered by Thiyagarajan K | 26th Nov, 2019, 09:11: AM