# Calculate Angles for Diffraction Grating 1st & 2nd Order Maxima

• AClass

## Homework Statement

Light with wavelengths of 520 nm and 630nm passes through a diffraction grating that contains 6000 lines/cm.

1) Calcualte the angles for the first and second order maxima that would appear on the screen

## Homework Equations

sin(Theta)m = m(Lamda)/d

## The Attempt at a Solution

[6000 lines/cm]^-1 = 1.667x10-4 cm/line = 1.667x10-6 m/line

d=1.667x10-6 m

-light 1- m=1

sin(Theta)1=[(1)(5.20x10^-7m)]/[1.667x10-6m]
Theta 1 = 22.2 degrees

Am I on the right track? I just have to for the other 3 situations?

## Homework Equations

sin(Theta)m = m(Lamda)/d
That should be:
sin(Theta) = m(Lamda)/d​
No "m" on the left side of the equation. This makes no difference when m=1, but you'll get the wrong answer when m=2.

## The Attempt at a Solution

[6000 lines/cm]^-1 = 1.667x10-4 cm/line = 1.667x10-6 m/line

d=1.667x10-6 m

-light 1- m=1

sin(Theta)1=[(1)(5.20x10^-7m)]/[1.667x10-6m]
Theta 1 = 22.2 degrees
It looks like you really used 630 nm, not 520 nm here.
Am I on the right track? I just have to for the other 3 situations?
You're close to the right track, see my comments above.