Question

A diffraction grating having 20000 lines per inch is better than that having 15000 lines per inch. Why?​

Answer 1

Answer:

as small space is wanted please thank me

Answer 2

A diffraction grating:

Explanation:

A diffraction grating is the number of lines per unit length.

∴$\displaystyle d = \frac {1} { N }$

where N is no of lines.

i.e.  d ∝$\displaystyle \frac {1} { N }$

d is inversely proportional to N.

As N = 20000 , d = 0.00005   &

As N = 15000 , d = 0.000006

i.e.   0.00005  > 0.000006

∴ A diffraction grating having 20000 lines per inch is better than that having 15000 lines per inch.