Subject :NSO Class : Class 9
Sound waves travel at 350 ms-1 through warm air and at 3500 ms-1 through brass. The wavelength of a 700 Hz acoustic wave as it enters brass from warm air
ADecrease by a factor 10.
BIncrease by a factor 20.
CIncrease by a factor 10.
DDecrease by a factor 20.
Ans 1:
Class : Class 9
the wave length in air by v=n.lemda, so 350 = 700 . wavelength so wave length = 0.5 m
Now when it enters in brass, v = 3500 m/s, so new wavelength = 3500 / 700 = 5 m.
So answer is option A, i.e. wavelength will be increased by a factor of 10.