Experiment-diffraction grating convert lambda wavelength of

Question

Diffraction Grating

  DATA TABLE:

λ of laser (nm)	L (m)	Several Δx Values (m)	Δxavg	θ (tan -1 Δxavg /L)

Part 1:

Calculations:

1. Convert λ, wavelength, of laser from nm to m. Remember 1 nm = 1 x 10 ^-9 m.
2. Average all Δx values to get one Δx_avg.
3. Calculate the angle θ from tan θ = Δx_avg/L.
4. Find sin θ.
5. Solve for d using n λ = d sin θ; i.e. d = n λ/sin θ.
6. Use d to find d^-1, i.e. how many lines there are per mm of diffraction grating.

Part 2:

λ of laser (m)	Distance to wall (m)	Measured values of n (m)	Average change in n (m)	Calculated theta
633 * 10^-9

Calculate theta:  tan^-1 (average distance between dots on wall) / (distance from card to wall)

Calculate d:  wavelength / sin theta

Calculate number of grooves per mm: 1/d

Calculate number of grooves on CD = (grooves /mm) (radius of CD- grooved part only)