Light from a 600 nm laser is shown through a single slit of unknown width. If a screen is placed 4.5 m behind the slit captures a diffraction patter with a central bright fringe of width 20 mm, what is the width of the single slit?

• A. 0.13 mm
• B. 0.11 mm
• C. 0.44 mm
• D. 0.26 mm

Answer: (D)

Verified step by step guidance

1. Understand the problem: We are dealing with single-slit diffraction, where light passing through a slit creates a pattern of bright and dark fringes on a screen. The width of the central bright fringe is related to the width of the slit.
2. Identify the formula for single-slit diffraction: The width of the central bright fringe (W) is given by the formula: W = 2 * L * λ / a, where L is the distance from the slit to the screen, λ is the wavelength of the light, and a is the width of the slit.
3. Substitute the known values into the formula: We have L = 4.5 m, λ = 600 nm (which is 600 x 10^-9 m), and W = 20 mm (which is 20 x 10^-3 m).
4. Rearrange the formula to solve for the width of the slit (a): a = 2 * L * λ / W.
5. Perform the calculation using the rearranged formula to find the width of the slit. Ensure units are consistent when substituting values into the formula.