The displacement y of a particle in a medium can be expressed as \[y={{10}^{-6}}\sin (100t+20x+\pi /4)m,\]where t is in second and\[x\]in metre. The speed of the wave is
A) 2000m/s
B) 5 m/s
C) 20 m/s
D) 57cm/s
Correct Answer:
B
Solution :
The speed of the wave\[v=\frac{\omega }{k}=\frac{100}{20}=5m/s\]