A slit of width a is illuminated by light of wavelength . The linear separation between 1^ st and 3^ rd minima in the diffraction pattern produced on a screen placed at a distance D from the slit system is _____.

Step-by-step solution

The position of the n^ th minimum in a single slit diffraction pattern on a screen at distance D is given by y_n = n D a . For the 1^ st minimum, n = 1 , so y₁ = D a . For the 3^ rd minimum, n = 3 , so y₃ = 3 D a . The linear separation between the 1^ st and 3^ rd minima on the same side of the central maximum is y = y₃ - y₁ . y = 3 D a - D a = 2 D a . Answer: 2 D a