Double-slit interference: In a two-slit experiment, the slit separation is 3.00 × m. The interference pattern is recorded on a flat screen-like detector that is 2.00 m away from the slits. If the seventh bright fringe on the detector is 10.0 cm away from the central fringe, what is the wavelength of the light passing through the slits?
A) 100 nm
B) 204 nm
C) 214 nm
D) 224 nm
E) 234 nm

Question

Double-slit interference: In a two-slit experiment, the slit separation is 3.00 ×  m. The interference pattern is recorded on a flat screen-like detector that is 2.00 m away from the slits. If the seventh bright fringe on the detector is 10.0 cm away from the central fringe, what is the wavelength of the light passing through the slits?
A) 100 nm 
B) 204 nm 
C) 214 nm 
D) 224 nm 
E) 234 nm

Quizplus · Accepted Answer

We can use the equation for double-slit interference:

y = (mλL) / d

where y is the distance from the central maximum to the mth bright fringe, λ is the wavelength of the light, L is the distance from the slits to the screen, d is the distance between the two slits, and m is the order of the fringe.

In this case, we know that d = 3.00 × 10^-6 m, L = 2.00 m, m = 7, and y = 0.100 m. Solving for λ, we get:

λ = (y * d) / (m * L) = (0.100 m * 3.00 × 10^-6 m) / (7 * 2.00 m) = 2.14 × 10^-7 m

Converting to nanometers, we get 214 nm. Therefore, the answer is C: 214 nm.

Double-Slit Interference: in a Two-Slit Experiment, the Slit Separation Is