In a Young's double-slit experiment, the slits are separated by 0.28 mm and the screen is placed 1.4 m away. The distance between the central bright fringe and the fourth bright fringe is measured to be 1.2 cm. Then the wavelength of light used in the experiment is .

Question

Accepted Answer

(3) 600 nm. Given: d = 0.28 mm = 2.8×10⁻⁴ m, D = 1.4 m, and the fourth bright fringe at x₄ = 1.2 cm = 1.2×10⁻² m. Idea: bright fringes sit at xₙ = (nλ D)/d, so the measured position of a fringe of known order fixes the wavelength. Rearranged with n = 4, λ = (x₄ d)/(4D). λ = ((1.2×10⁻²)(2.8×10⁻⁴))/(4 × 1.4) = (3.36×10⁻⁶)/(5.6). λ = 6×10⁻⁷ m. The wavelength used is 600 nm.

In a Young's double-slit experiment, the slits are separated by 0.28 mm and the screen is placed 1.4 m away. The distance between the central bright fringe and the fourth bright fringe is measured to be 1.2 cm. Then the wavelength of light used in the experiment is ________.

Step-by-step solution

Why the other options are wrong