Light of wavelength 575 nm passes through a double-slit and the third order bright fringe is seen at an angle of 6.5° away from the central fringe.What is the separation between the double slits?
A) 5.0 µm
B) 10 µm
C) 15 µm
D) 20 µm
E) 25 µm

Question

Quizplus · Accepted Answer

We can use the equation:

d*sin(θ) = m*λ

Where d is the separation between the double slits, θ is the angle of the fringe, m is the order of the fringe (in this case, m = 3), and λ is the wavelength of the light.

Rearranging this equation, we can solve for d:

d = m*λ/sin(θ)

Plugging in the values given in the problem:

d = 3*(575 nm)/(sin(6.5°))

d = 15 µm

Therefore, the separation between the double slits is 15 µm (option C).

Light of Wavelength 575 Nm Passes Through a Double-Slit and the Third