Q. The phase difference between two points separated by 0.8 m in a wave of frequency 120 Hz is$0.5\pi$. The wave velocity is
A) $144ms^{- 1}$
B) $384ms^{- 1}$
C) $256ms^{- 1}$
D) $720ms^{- 1}$
Explanation
(b) Here , $n = 120\ Hz,$
$x = 0.8m,\phi = 0.5\pi$.
From $\phi = \frac{2\pi}{\lambda}x;\lambda = \frac{2\pi x}{\phi} = \frac{2\pi \times 0.8}{0.5\pi} = 3.2\ m$
$v = n\lambda = 120 \times 3.2 = 384\ ms^{- 1}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.