Question

5: How to find the grating element of a given diffraction grating having 1500 Lines Per Inch (LPI)?
O In one inch available lines are 15000 it means number of slits available. grating element will be-1 inch/15000
O standard value which we can determine by the formula
O None of these
O by using the formula nl - d sin a​

Answer 1

Answer:

Correct answer

(A) In one-inch available lines are 15000 which means the number of slits available. The grating element will be $\frac{1 inch}{15000}$

Explanation:

Let N be the number of parallel slits, each pf width 'a' and separated by opaque spaces 'b'.

Then, the distance between the centers of the adjacent slit is

$d = a +b$

The number of lines per inch of the grating will be =

$a+b =\frac{1 inch}{No. of lines in 1inch}$