Answer: 1500 m/sec. ( b )
Solution:
V= f (λ)
Speed = frequency. Wavelength
And frequency = 1/time period
First we will find the frequency :
Frequency = 1/time period
1/0.006 = 166.67 Hz
Using this in the equation:
Speed = frequency. Wavelength
V= f (λ)
9 × 166.67
= 1500.03 ≈ 1500
V (Speed) = 1500 m/s.
Note: Do not forget to mention the units or otherwise they may cost you marks!