Which of the following statements are incorrect?

Options

A. Wave pulses in strings are transverse waves.
B. Sound waves in air are transverse waves of compression and rarefaction.
C. The speed of sound in air at `20^@C` is twice that at `5^@C`.
D. A 60dB sound has twice the intensity of a 30 dB sound.

Answer

B, C, D

Explanation

`vpropsqrtT`
`60dB=10log((I_1)/(I_0))`
`30dB=10log((I_2)/(I_0))`
`30=10log((I_1)/(I_2))implies(I_1)/(I_2)ne2`