Diffraction of sound waves is more evident than light waves in daily life because:

$A$ parallel beam of light is incident on a tank filled with water up to a height of $61.5 \,mm$ as shown in the figure below. Ultrasonic waves of frequency $0.5 \,MHz$ are sent along the length of the water column using a transducer placed at the top and they form longitudinal standing waves in the water. Which of the schematic plots below best describes the intensity distribution of the light as seen on the screen? (Take the speed of sound in water to be $1500 \,m/s$)

$Assertion :$ Transverse waves are produced in a very long string fixed at one end. Only a progressive wave is observed near the free end.
$Reason :$ Energy of the reflected wave does not reach the free end.

$A$ composite string is made up by joining two strings of different masses per unit length $\mu$ and $4\mu$. The composite string is under the same tension. $A$ transverse wave pulse $Y = (6 \text{ mm}) \sin(5t + 40x)$,where $t$ is in seconds and $x$ in meters,is sent along the lighter string towards the joint. The percentage of power transmitted to the heavier string through the joint is approximately ..... $\%$

If $T$ is the reverberation time of an auditorium of volume $V$,then:

The persistence of sound in a room after the source of sound is turned off is called reverberation. The measure of reverberation time is the time required for sound intensity to decrease by $60 \,dB$. It is given that the intensity of sound falls off as $I = I_0 \exp(-c_1 \alpha)$,where $I_0$ is the initial intensity,$c_1$ is a dimensionless constant with value $1/4$. Here,$\alpha$ is a positive constant which depends on the speed of sound $v_s$,volume of the room $V$,reverberation time $t$,and the effective absorbing area $A_e$. The value of $A_e$ is the product of the absorbing coefficient and the area of the room. For a concert hall of volume $V = 600 \,m^3$,the value of $A_e$ (in $m^2$) required to give a reverberation time of $t = 1 \,s$ is closest to (speed of sound in air $v_s = 340 \,m/s$):