Diffraction Grating Calculation

00:00 3 marks

Light of wavelength $650\,\text{nm}$ is incident normally on a diffraction grating. The first-order maximum is observed at an angle of $15°$ to the central maximum.

Part a

5 minutes 3 marks

Question

Calculate the number of lines per millimetre on the diffraction grating. [3]

Hint Hint

Hint

Use the diffraction grating equation $n\lambda = d\,\sin\theta$ with $n=1$, and solve for $d$ then compute $1/d$ and convert to lines per mm.

Answer Answer
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Explanation Explanation

Answer Answer

Complete Answer

$398 \text{ lines/mm}$

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