NCERT Class 9 Physics Formative Assessment of Sound CBSE Board Sample Problems

Doorsteptutor material for CBSE/Class-9 is prepared by world's top subject experts: get questions, notes, tests, video lectures and more- for all subjects of CBSE/Class-9.

Short Answer Based questions

1) Arrange the speed of sound in Steel, water and air in ascending order?

2) What is the relation between frequency and time period of the wave?

3) Sound waves are transverse waves True or False?

4) Arrange the speed of these waves in air in descending order a) light b) Sound C) Supersonic aircraft?

5) What is an echo?

6) What are three characteristics of the sound?

7) What is the audible range of sound frequencies for human ear?

8) What is Reflection of sound?

Match the column

Match the Column
Column A

(Frequency)

Column B

(Sound range they fall)

5 HzAudible range
25000 HzInfrasonic range
25 HzUltrasonic range
250 Hz
10 Hz
120000 Hz

Match the column

Match the Column
Column AColumn B
The maximum disturbance caused by the waveWavelength
The distance travelled by a wave per secondFrequency
The no of complete vibrations per secVelocity
The distance between one crest of wave and next oneAmplitude
When we change a feeble sound too loud sound, we increase itsTime period
When we change the pitch. what is getting changed

Table type question

Table Type Question
Sound velocityFrequencyWavelengthTime periodAudible/Ultrasonic/Infrasonic
330 m/s550Hz???
500 Hz68m??
343.4m/s?1.7cm??

Fill in the blanks

1) Sound waves ________travel in vacuum

2) The speed of sound depend son ________And ________

3) The soft and porous materials are bad ________of sound

4) The speed of the highly penetrating ultrasonic waves are ________those of audible sound waves

5) The________ sound are produced before the main shock wave of earth quake

Solution

1) Do not

2) Nature of the material, temperature

3) Reflectors

4) Same

5) Infrasonic

Crossword Puzzle

Crossword Puzzle

Across

4. It is used break kidney stones into fine grains

7. The unit of frequency

8. The loudness of the sound depends on this

9. Medical instrument used by the doctors for listening to heartbeats

10. It is the region of low pressure in longitudinal wave

Solution:

Across

Ultrasound, Hertz. Amplitude. Stethoscope, rarefaction

Down

1. Apparatus used to find the depth of the sea

2. It converts sound wave frequency into electrical impulses

3. A vibrating simple pendulum produces this type of sound

5. It is the sensation of a frequency

6. Elevation in a transverse wave

Solution:

Down

Sonar, Cochlea, infrasonic, Pitch, crest