A progressive wave equation is represented by Y= a sin(150 πt – πx/4). if the phase difference of a progressive wave is 45°, the value of x in the equation is

A. 3 cm
B. 4 cm
C. 1 cm
D. 2 cm

Correct Answer:

Option C – 1 cm

Explanation

Y = sin π(150πt – πx/4)
comparing the above with the standard wave equation:
Y = A sin π ((2vt)/λ – (2x)/λ)
=> the phase difference x/4 = 2x/λ
∴ 1/4 = 2/λ => λ = 8cm
∴ 2πx/8 = 45°
since π = 180°

45° X 8 = 2 X 180° x

∴ x = 1cm