Home / Aptitude Tests / Physics / A progressive wave e...

A progressive wave equation is represented by y = a sin(1...

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 is C

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