Question
Question: For the wave shown in figure, the wavelength and frequency, if its speed is 320 m/sec, are – 
A
8 cm , 400 Hz
B
80 cm, 40 Hz
C
8 cm, 4000 Hz
D
40 cm, 8000 Hz
Answer
8 cm, 4000 Hz
Explanation
Solution
As per fig.
l + l + l/2 = 20 cm
or 25λ = 20
\ l = 8 cm = 0.08 m
Q v = nl
\ 320 = n (0.08)
\ n =
= 4000 Hz
