StudentAidUnit 12: Waves — Numericals
10th Class Physics · Unit 12: Waves
12.1.The wavelength of a wave is 2 metres and its frequency is 5 Hz. What is the speed of the wave?
Given
Wavelength
lambda = 2 m
Frequency
f = 5 Hz
To find
Speed of the wave
v = ?
Formula
Wave equation
v = flambda
Working
Substitute values
v = 5 × 2
Result
Speed
v = 10 m/s
12.2.A wave travels at a speed of 300 ms⁻¹ and has a wavelength of 3 metres. Calculate its frequency.
Given
Speed of the wave
v = 300 m/s
Wavelength
lambda = 3 m
To find
Frequency
f = ?
Formula
Wave equation
v = flambda
Working
Rearrange for frequency
f = vlambda
Substitute values
f = 3003
Result
Frequency
f = 100 Hz
12.3.A sound wave has a frequency of 250 Hz and a speed of 340 ms⁻¹. Find its wavelength.
Given
Frequency of sound wave
f = 250 Hz
Speed of sound
v = 340 m/s
To find
Wavelength
lambda = ?
Formula
Wave equation
v = flambda
Working
Rearrange for wavelength
lambda = vf
Substitute values
lambda = 340250
Result
Wavelength
lambda = 1.36 m
12.4.A wave has a frequency of 50 Hz. How much time does it take to complete one wave?
Given
Frequency
f = 50 Hz
To find
Time period
T = ?
Formula
Relation between period and frequency
T = 1f
Working
Substitute values
T = 150
Result
Time period
T = 0.02 s
12.5.A wave has a wavelength of 0.5 m and frequency of 200 Hz. Calculate the speed of the wave.
Given
Wavelength
lambda = 0.5 m
Frequency
f = 200 Hz
To find
Speed of the wave
v = ?
Formula
Wave equation
v = flambda
Working
Substitute values
v = 200 × 0.5
Result
Speed
v = 100 m/s
12.6.The time period of a wave is 0.02 seconds. Calculate the frequency of the wave.
Given
Time period
T = 0.02 s
To find
Frequency
f = ?
Formula
Relation between frequency and period
f = 1T
Working
Substitute values
f = 10.02
Result
Frequency
f = 50 Hz