Required Practical 2: Diffraction Grating

Question 1

Describe an investigation to find the wavelength of laser using a diffraction grating

Answer 1

1) adjust apparatus to that D=1m, measured using a meter ruler
2) measure the distance between the fringes, h1 and h2 on either side of the central maximum and find mean
3) find slit separation by using 1/ number of slits per meter
4) find angle 1 and 2 by arctan (h/D)
5) find wavelength for each angle and calculate mean