Question

Two point sources, vibrating in phase, produce an interferencepattern in a ripple tank. If the frequency is increased by 20%, thenumber of nodal lines:

A) is increased by 20%
B) is increased by 40%
C) remains the same
D) is decreased by 20%
E) is decreased by 40%

Answer 1

Answer:

option A

Explanation:

given,

frequency is increased by 20%

we know,

$\dfrac{x_n}{L}d = (n-\dfrac{1}{2})\times \lambda$...........(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