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# Numerical problems

8th Science : Chapter 6 : Sound : Numerical Example solved problems and book back Numerical problems Questions with Solution

Problem 1

A sound has a frequency of 50 Hz and a wavelength of 10 m. What is the speed of the sound?

Solution

Given, n = 50 Hz, λ = 10m

v = nλ

v = 50 × 10

v = 500 ms-1

Problem 2

A sound has a frequency of 5 Hz and a speed of 25 ms-1. What is the wavelength of the sound?

Solution

Given, n = 5 Hz, v = 25 ms-1

v = nλ

λ = v/n = 25/5 = 5 m

1. Ruthvik and Ruha hear a gunshot 2 second after it is fired. How far away from the gun they are standing? (Speed of sound in air is equal to 330ms-1)

Solution :

Given data : time t = 2 s

Speed of sound V = 330 ms-1

To find : Distance d = ?

Formula : Distance = Speed × time

Distance d = 330 × 2 = 660 m

2. A sound wave travels 2000 m in 8 s. What is the velocity of the sound?

Solution :

Given data :

Distance travelled by a sound wave d = 2000 m

time taken t = 8 s

To find : Velocity of sound V = ?

Formula:

Volcity V = distance (d) / time(I)

V= 2000/8 = 250ms-1

3. A wave with a frequency of 500 Hz is traveling at a speed of 200 ms-1. What is the wavelength?

Solution :

Given data : Frequency n = 500 Hz

Speed V = 200 ms-1

To find : Wavelength λ = ?

Formula : Wavelength λ = Velocity (V) / Wavelength (n)

λ = 200/500 = 2/5= 0.4 m

4. What is the frequency of a mechanical wave that has a velocity of 25 ms 1 and a wavelength of 12.5 m?

Solution :

Given data : Frequency n = ?

Velocity V = 25 ms-1

Wavelength λ = 12.5m

To find: Frequency n = ?

Formuls: Frequency n  = V(Velocity) / λ(Wavelength)

n = 25/12.5 = 2 Hz

Tags : Sound | Chapter 6 | 8th Science , 8th Science : Chapter 6 : Sound
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