A diffraction grating with 260 lines per mm is used in an experiment to study the visible spectrum of a gas discharge tube. At what angle from the beam axis will the first order peak occur if the tube emits light with wavelength of 580.2 nm? 8.676 deg
Which I got to be =8.676degree

Question

A diffraction grating with 260 lines per mm is used in an experiment to study the visible spectrum of a gas discharge tube. At what angle from the beam axis will the first order peak occur if the tube emits light with wavelength of 580.2 nm? 8.676 deg 
Which I got to be =8.676degree

anonymous · Answer

But what would be part two..."At what angle will the second order peak occur?"

joannablackwelder · Answer

I agree with your answer. To find the second order peak, you need to make n=2.

joannablackwelder · Answer

$$\lambda=\frac{dsin \theta }{n }$$

anonymous · Answer

I did that and it says its wrong @JoannaBlackwelder

joannablackwelder · Answer

Hm, that's weird. Did you get 17.56 deg?

anonymous · Answer

no lol! How did you do that?? and thank you!!

joannablackwelder · Answer

Using the formula I gave you with n=2. :)

anonymous · Answer

huh...I must have been doing something wrong but thanks again! I really appreciate it :)

joannablackwelder · Answer

What did you get?

joannablackwelder · Answer

No worries. Happy studies!

anonymous · Answer

Okay so i am doing 2*580.2E-9/260 then taking the inverse sin of that but i cant get 17.60...could you show me the formula?

joannablackwelder · Answer

From the formula I gave you I plugged in λ = 580.2E-9, d=1/260,000 (to put it in slits/m), and n=2

joannablackwelder · Answer

Then solve as you suggested using inverse sin.

anonymous · Answer

Okay thank yoU!!!!