Light shines through a single slit whose width is 5.7 10-4 m. A diffraction pattern is formed on a flat screen located 4.0 m away. The distance between the middle of the central bright fringe and the first dark fringe is 3.9 mm. What is the wavelength of the light

Answer: 557nm

Explanation:

Visible light has been known to have its wavelengths in the range between 400 to 700 nanometres (nm), or 4*10^-7 to 7*10^-7 m. This wavelength is between infrared and ultraviolet. Infrared has longer wavelengths and while on the other hand ultraviolet has shorter wavelengths. The wavelength of visible light has a frequency of approximately 430 to 750 terahertz (THz).

tanΦ = 0.0039/4 = 9.75*10^-4

Φ = tan^-1 (9.75*10^-4)

Φ = 0.056

λ = (5.7*10^-4) * sin 0.056

λ = 5.57*10^-7m

λ = 557nm