The lines in a grating are uniformly spaced at

[AnnieMoo]

Homework Statement

The lines in a grating are uniformly spaced at 1530 nm. Calculate the angular separation of the second order bright fringes between light of wavelength 600 nm and 603.11 nm. Answer in __mrad

Homework Equations

Theta = sin-1 ((m*lambda*2)/(d))

The Attempt at a Solution

d = 1530 nm
m = 2
lambda1 = 600 nm
lambda2 = 603.11

Theta1 = sin-1 ((2*600)/(1530))
= 51.66

Theta2 = sin-1 ((2*603.11)/(1530))
= 52.03

Theta2 - Theta1 = (52.03)-(51.66) = 0.37

The answer is apparently wrong. Please help! I would really appreciate it. Thanks!

 

[ehild]

Hi AnnieMoo,

In what units have you got the separation angle? And what is said in the problem text?

ehild