Question

The equation of a wave travelling on a string is $y=4sin\frac{\pi }{2}⟮8t-\frac{x}{8}⟯$ . If x and y are in cm, then velocity of wave is

[MP PET 1990]

• A. 64 cm/sec in - x direction
• B. 32 cm/sec in - x direction
• C. 32 cm/sec in + x direction
• D. 64 cm/sec in + x direction

Answer 1

The correct option is D

64 cm/sec in + x direction

The given equation can be written as $y=4sin⟮4\pi t-\frac{\pi x}{16}⟯\Rightarrow \left(v\right)=\frac{\text{co-efficient of t(w)}}{\text{co-efficient of x(K)}}$

$\Rightarrow v=\frac{4\pi }{\pi /16}=64cm/sec$ along +x direction.