Two slits question

+2 votes

A laser beam is incident on two slits with a separation of 0.180 mm, and a screen is placed 5.25 m from the slits. An interference pattern appears on the screen. If the angle from the center fringe to the first bright fringe to the side is 0.182°, what is the wavelength of the laser light?

asked Apr 22, 2012 in Physics by swhite5 (68 points)

1 Answer

+1 vote

You would use the Young's double-slit model to solve this equation.

d*sin(theta) = m* λ     (*where d=distance between the slits, m is the order number of the fringes, and  λ is the wavelength,)

solving for λ

λ = (d*y)/(L*m)

You are given:

d = 0.180 *10^-3 m

theta = 0.182°

m = 1 because question states first bright fringe


Plug values into formula and solve:

λ = (d*y)/(L*m)

answered Apr 22, 2012 by kirby ~Expert~ (3,020 points)
edited Apr 22, 2012 by kirby

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