Question

if there are 10000lines per inch in a plane diffracting grating,then the grating element is
(a) 0.001 cm
b. 0.0001 cm
c. 0.000254 cm
d. 0.254 cm ​

Answer 1

Answer:

Given parameters are

θ=20∘.

N =1000 limes per mm length.

So, d =1N

i.e. d = 11000 mm

i.e. d = 10−6 m.

for n =1,

using formula , n λ=dsin(θ)

λ=dsin(θ putting n =1

= 10−6×sin20∘

= 3.4×10−5m

Thus wavelength will be 3.4×10−5m

Q.2: