Question

Physics Question!!!
Two children are at opposite ends of an aluminium rod. One strikes the end of the rod with a stond. Find the ratio of times taken by the sound wave in air and in aluminium to reach the second child.​

Answer 1

We have to find the ratio of time taken by the sound waves to reach the other end of aluminium rod and time taken by the sound waves to travel through air.

Let the size of aluminium rod be x.

We know that,

$\sf \: time = velocity \: \times displacement$

In air,

$\sf \: t_1 = 340x - - - - - (1)$

In the aluminium rod,

$\sf \: t_2 = 6320x - - - - - (2)$

Dividing both the equations, we get :

$\implies \sf \: t_1 : \: t_2 = 1 :18.58 \: (approx)$ .

Answer 2

Answer:

Given :-

• Two children are at opposite ends of an aluminium rod.
• One strikes the ends of the rod with a stone.

To Find :-

• What is the ratio of times taken by the sound wave in air and in aluminium to reach the second child.

Solution :-

Let, the length of aluminium rod be d

❶ Speed of sound in air = 340 m/s

Time taken of sound in air = $\dfrac{d}{340}$ ..... equation no (1)

❷ Speed of sound in alluminium = 6420 m/s

Time taken of sound in alluminium = $\dfrac{d}{6420}$ ..... equation no (2)

By dividing the equation no (1) and (2) we get,

➠ $\dfrac{Time\: taken\: of\: sound\: in\: air}{Time\: taken\: of\: sound\: in\: alluminium}$

⇒ $\sf\dfrac{\dfrac{d}{340}}{\dfrac{d}{6420}}$

⇒ $\dfrac{6420}{340}$

➥ 18.89 (approx)

$\therefore$ The ratio of time taken by the sound wave in air and in aluminium to reach the second child is 1 : 18.89 (approx) .