Question

Describe how you used the interference pattern to figure out the wavelength of the laser. It is required to draw the observed interference pattern here and clearly specify the parts you used for the calculation (Hint: In double-slit interference experiment, given the position of the ?-th bright spot as ?, the distance between the slit and the screen as ?, and the distance between the two slits as ?, the wavelength of light source can be expressed as ? = (? × ?)/(? × ?). ? and ? are already given. The remaining part is to figure out how to obtain ? and ? from the data sheet).

Laser 1 wavelength = 700nm

Laser 2 wavelenth = 600nm

Data

Ymax = 16.00mm

Ymin = 14.00mm

Separation between slits: d = 0.30mm

Slit-screen distance: L = 1500.00mm

What is m and y?

Answer 1

for the double slit experiemnt
for the mth bright spot
ym = m*lambda*(L/d)
L is distance from the screen, d is slit seperation

lamdba1 = 700 nm
lambda2 = 600 nm

Ymax = 16 mm
Ymin = 14 mm

d = 0.3 mm
L = 1500 mm

hence
ym = m*lambda*(1500/0.3) = 5000*m*lambda

for laser 1,
16 = m*700*10^-6*5000
m = 4.57142857142

for laser 2,
16 = m*600*10^-6*5000
m = 5.333333333

diagram describing the calculation of dobule slit experiment is as under:

it shows how interference of two waves leads to an interference pattern liek observed in youngs double slit experiment