Q.

The equation of a transverse wave travelling along a string is y(x,t)=4.0 sin [20×10–3x+600 t] mm, where x is in the mm and t is in second. The velocity of the wave is           [2025]

1 + 30 m/s  
2 – 60 m/s  
3 – 30 m/s  
4 + 60 m/s  

Ans.

(3)

y=4 sin (20×10–3x+600 t)

Here, ω = 600 and k = 20×10–3

∴ v=ωk=60020×10–3

          =30×10+3 mm/s=30 m/s

and direction is towards –ve x-axis

∴  v = – 30 m/s