Answer:
option A
Explanation:
given,
frequency is increased by 20%
we know,
[tex]\dfrac{x_n}{L}d = (n-\dfrac{1}{2})\times \lambda[/tex]...........(1)
where
x_n is the perpendicular distance between the point the interference pattern is obtained,
L is the distance between the center of the two point sources
and λ is the wavelength of light.
If the frequency is increased by 20%, then the number of nodal lines is increased by 20%.
From equation (1),we observe that the frequency is directly proportional to the number of nodal lines.
Hence, the correct answer is option A
