What is the quantity transmitted with propagation of longitudinal waves through a medium?

1

(a)

Propagation of longitudinal waves through a medium leads to transmission of energy through the medium.

What is the nature of water waves produced by a motorboat sailing in water ?

1

(a)

Water waves produced by a motorboat sailing in water are both longitudinal and transverse.

How speed of sound waves in air varies with humidity?

1

(a)

Speed of sound waves in air increases with increases with increase in humidity. This is because presence of moisture decreases the density of air.

The displacement of an elastic wave is given by the function y = 3sin \(\omega \)t + 4cos\(\omega \)t Where, y is in cm and t is in second.Calculate the resultant amplitude.

1

(a)

The resultant amplitude will be
\(y=\sqrt { { y }^{ 2 }_{ 1 }+{ y }^{ 2 }_{ 2 } } =\sqrt { 9+16 } =\sqrt { 25 } =5cm\)

Sound waves of wavelength \(\lambda \) travelling in a medium with a speed of vm/s enter into another medium where its speed is 2vm/s.Wavelength of sound waves in the second medium is

1

(a)

Frequency in the first medium, v =\(\frac { v }{ \lambda } \)
Frequency will remain same in the second medium, as the source.
\(\Rightarrow v^{ , }=v\Rightarrow \frac { 2v }{ \lambda ^{ ' } } =\frac { v }{ \lambda } \Rightarrow { \lambda }^{ ' }=2\lambda \)