Question

1.
A progressive wave in a stretched string has a speed of 20 ms and a frequency of 100 Hz. What is
the phase difference between two points 25 mm apart?
A zero
B pi/4 rad
c pi/2 rad
D pi tad

Answer 1

Answer:

Option B

Explanation:

As we know phase difference is equal to

$\psi = \frac{2\pi }{\lambda} * \Delta$ ----Eq (1)

where

$\Delta$ is the physical difference between two points = 0.025 m

$\lambda$ is equal to $\frac{v}{f}$

$\lambda = \frac{20}{100} = 0.2$

Substituting the given values in above equation, we get -

$\psi$ =

$\frac{2\pi }{0.2} *0.025\\\frac{\pi }{4}$

Hence, option B is correct