Question

Calcutate the fourth-order resolution of a grating that is 8 cm long and is ruled at 185 lines/mm

Answer 1

$5.9 \times 10^4$ is the Resolution

Explanation:

• Light Passing through a single slit produces a pattern with  

a.) Very broad central maximum

b.) much fainter secondary maxima

• Light Passing through a double slit produces a pattern with  

a.)  broad central maximum

b.)  broad secondary maxima

c.) roughly equal intensities for secondary maxima

• Light Passing through a multiple sets of slits produces a pattern that follows the sequence

a.) narrow maxima  

b.) more and more equal intensity for maxima farther away from center

We know that,

• Resolution is the product of number of orders for the number of lines in a grating of a predefined length.

Or  

Resolution, r = Number of orders $\times$ Length of Grating $\times$ Number of Lines in Grating

= $4(80\ mm)(185\ \frac {lines}{mm})$

= $5.9 \times 10^4$