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

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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 Hz

Audible range

25000 Hz

Infrasonic range

25 Hz

Ultrasonic range

250 Hz

10 Hz

120000 Hz

Match the column

Match the column

Column A

Column B

The maximum disturbance caused by the wave

Wavelength

The distance travelled by a wave per second

Frequency

The no of complete vibrations per sec

Velocity

The distance between one crest of wave and next one

Amplitude

When we change a feeble sound too loud sound, we increase its

Time period

When we change the pitch. what is getting changed

Table type question

Table type question

Sound velocity

Frequency

Wavelength

Time period

Audible/Ultrasonic/Infrasonic

330 m/s

550Hz

?

?

?

500 Hz

68m

?

?

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

Crossword Puzzle

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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