$v_1$ and $v_2$ are the velocities of sound at the same temperature in two monoatomic gases of densities $\rho_1$ and $\rho_2$ respectively. If $\frac{\rho_1}{\rho_2} = \frac{1}{4}$,then the ratio of velocities $v_1$ and $v_2$ will be

$SONAR$ emits which of the following waves?

The minimum distance of the reflector surface from the source to hear the echo of sound is ..... $m$.

$A$ firecracker exploding on the surface of a lake is heard as two sounds a time interval $t$ apart by a man on a boat close to the water surface. Sound travels with a speed $u$ in water and a speed $v$ in air. The distance from the exploding firecracker to the boat is

$A$ person standing on an open ground hears the sound of a jet aeroplane coming from the north at an angle of $60^{\circ}$ with the ground level. However,he finds the aeroplane right vertically above his position. If $\upsilon$ is the speed of sound,what is the speed of the plane?

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: $A$ sound wave has higher speed in solids than gases.
Reason $R$: Gases have higher value of Bulk modulus than solids.
In the light of the above statements,choose the correct answer from the options given below: