Light of wavelength 570.00 nm is incident normally on a diffraction grating, and the third‑order maximum is observed to be 24.0∘ from the normal. how many slits per millimeter are marked on the grating?

Answer : The number of slits per millimeter marked on the grating are 238 slits/mm.

Explanation :

First we have to calculate the slit separation.

Formula used for a diffraction grating when maxima occur:

where,

d = slit separation = ?

a = angle =

= wavelength = 570.00 nm

n = order = 3

Now put all the given values in the above formula, we get:

Conversion used :

Now we have to calculate the number of slits per millimeter.

Therefore, the number of slits per millimeter marked on the grating are 238 slits/mm.

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