Question

If 670-nm light falls on a slit 0.0475 mm wide, what is the angular width of the central diffraction peak?

Answer 1

In double slit experiment we know that:

m* = d*sin

= arcsin (m*/d)

= angular width on one side = ?

m (for central diffraction) = 1

= wavelength of light = 670 nm = 670*10^-9 m

d = width of slit = 0.0475 mm = 0.0475*10^-3 m

So,

= arcsin (1*670*10^-9/(0.0475*10^-3))

= 0.0141 rad = angular width on one side

2 = angular width of central diffraction peak = 2*0.0141 = 0.0282 rad

(If you need answer in degree, then 0.0282 rad = 1.62 deg)

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