A plane sound wave of frequency 85.5Hz and velocity 342ms-1 is reflected from a vertical wall. At what distance from the wall does the wave have antinode?
A
2m
B
4m
C
1m
D
3m
Verified Correct Answer: C.
Physical Principles & Numerical Solution
If F = 85.5Hz, V = 342ms-1,
Then wavelength = V/F = 342/85.5 = 4m
Then if wavelength = 4m
=> wavelength/2 = 4/2 = 2m = NN,
Thus NA = wavelength/4 = 4/4 = 1m.
Source: Myschool Past Questions Archive (Record #7244)