Question

Determine the angular separation between central maximum and first order secondary maximum of the diffraction pattern due to a single slit of width `0.25 mm` when light of wavelength `5890 Å` falls on it normally.

Answer 1

Here, `theta = ?`
`d = 0.25 mm = 0.25 xx 10^(-3)m`
`lambda = 5890 Å = 5890 xx 10^(-10)m`
As is clear from Fig.,

angular separation between central maximum and first order secondary maximum is
`theta = (3)/(2)(lambda)/(d) - 0 = (3 lambda)/(2 d) = (3 xx 5890 xx 10^(-10))/(2 xx 0.25 xx 10^(-3))`
`= 3.534 xx 10^(-3) radian`