Worksheets › Class 9 › Sound Waves: Characteristics and Applications
Class 9 Sound Waves: Characteristics and Applications worksheet
CBSE Science. Waves, v = fλ, frequency and time period, echoes, SONAR, speed in media. Every sheet has 20 questions in three sections and an answer key, and the numbers change every time.
Sample questions
Real questions from this chapter, as the app sets them. Tap Answer to see the answer and working.
Section A · multiple choice
- 1.
A sound has frequency 220 Hz and wavelength 1.5 m. Its speed is:
- 146.67 m/s
- 165 m/s
- 660 m/s
- 330 m/s
Answer
(d) 330 m/s
v = fλ
- 2.
The time period of a sound wave is 0.4 ms. Its frequency is:
- 2,500 Hz
- 25,000 Hz
- 1,250 Hz
- 5,000 Hz
Answer
(a) 2,500 Hz
f = 1 ÷ T
- 3.
Sound cannot travel through:
- steel
- water
- a vacuum
- air
Answer
(c) a vacuum
it needs a medium
Section B · short answer
- 4.
A sound of frequency 100 Hz travels through air at 344 m/s. Find its wavelength and its time period.
Answer
λ = 3.44 m; T = 10 ms
λ = v ÷ f; T = 1 ÷ f
- 5.
A boy stands 196 m from a tall building and claps. After how long will he hear the echo? (Speed of sound = 344 m/s)
Answer
1.14 s
t = 2d ÷ v = 392 ÷ 344
Section C · long answer
- 6.
Describe an experiment to show that sound needs a medium to travel.
Answer
Hang an electric bell inside an airtight glass jar connected to a vacuum pump. Ring the bell: you hear it. Pump the air out slowly: the sound becomes fainter and almost stops, though the bell can still be seen ringing. So sound cannot travel through a vacuum.
Fresh sheets for your child
In the app, every Sound Waves: Characteristics and Applications sheet is new: the app remembers the questions your child has already had and leaves them out. Print the sheet as a PDF, or use notebook mode and write the answers in a notebook.
Coming soon for Android and iPhone.