# NIOS Class 10 Science & Technology Chapter 18 Solution

## NIOS Class 10 Science & Technology Chapter 18 Solution – Sound And Communication

NIOS Class 10 Science & Technology Solution Chapter 18 Sound And Communication. NIOS Class 10 Science & Technology Chapter 18 Question Answers Download PDF. NIOS Class 10 Science Notes.

### NIOS Class 10 Science & Technology Chapter 18 Solution

 Board NIOS Class 10th (Secondary) Subject Science and Technology (218) Topic Question Answer, Solution, Notes

CHAPTER: – 18.

(SOUND AND COMMUNICATION)

INTEXT QUESTIONS 18.1

1) Which sound wave will have its crests farther apart from each other – a wave with frequency 100 or a wave with frequency 500?

Ans: – As we all know, v=ny or v/n=y, here y= wavelength, v=velocity, n= frequency. So, it is clear that which have less frequency will be more wavelength as we all the more creates also.

2) If the velocity of sound is 330 metres per second (ms–1), what will be wave length if the frequency is 1000 Hertz?

Ans: – We know, v=ny,

Here, v=velocity= 330m/s, n=frequency= 100Hz, y=wavelength=?

So, y= 330/100 = 0.33m.

3) What is the approximate audible range of frequency for humans?

Ans: – The approximate audible range of frequency for human is 20HZ to 20KHZ.

INTEXT QUESTIONS 18.2

1) Does a wave transfer energy or material?

Ans: – Yes, a wave transfer energy or material.

2) How do mechanical and electromagnetic waves differ?

Ans: – The mechanical wave needs a medium for the propagation whereas the electromagnetic wave doesn’t need any medium for the propagation.

3) What is the difference between a transverse and longitudinal wave?

Ans: – The direction of propagation in a transverse wave always in perpendicular to oscillation whereas in longitudinal wave the direction of propagation is always be parallel to the oscillation.

4) Do transverse waves form in solid?

Ans: – In solid the transverse wave forms.

INTEXT QUESTIONS 18.3

1) What is the unit to measure sound intensity?

Ans: – In decibel unit sound is measure.

2) Why do they have many holes at the side of a flute lengthwise?

Ans: – The holes in flute side are for the changing the length of vibration of the sound wave by closing or opening it.

INTEXT QUESTIONS 18.4

1) Give three examples of devices that make use of microphones or speakers or both.

Ans: – In television, telephone, and in radio we use the microphone or speakers or both.

2) In a condenser microphone, what will happen if the diaphragm is made very heavy?

Ans: –In case if the diaphragm of the condenser microphone is very heavy then we will see that high frequency will not produce in that.

INTEXT QUESTIONS 18.5

1) List some uses of satellites.

Ans: – Uses of satellite is-

• Communication
• Earth observing.
• Monitoring
• Surveying
• Photographing

2) If a satellite equipped with cameras remains fixed at one height above ground even as earth rotates and moves in its orbit, what is its possible use?

Ans: – satellite is stationery and earth below it keeps moving because of this view will keep changing. So, without the satellite moving this camera will see whole surface of earth.

3)Arrange the low orbit, geostationary and polar satellites in decreasing order of altitude above Earth (the highest one comes first).

Ans: – The order is geostationary> polar>lower satellite.

4)Which of the satellites are preferred for communication application?

Ans: – Geostationary satellite.

TERMINAL EXERCISE

1) Fill in the blanks:

(i) Sound travels at a ……lower………… velocity than light.

(ii) When there is lightning, we first ……saw………… and then hear it.

(iii) SONAR makes use of …ultrasonic…………… waves while RADAR makes use of …infrasonic…………… waves.

(iv) Microphone converts sound into ……electrical signal………… while speaker converts electric signal into ………mechanical energy………

2) Multiple choice type questions

(i) Which satellite will see a wider area on Earth?

(a) A low earth orbit satellite (b) A high earth orbit satellite

(c) A medium earth orbit satellite.

Ans: – Option(b).

(ii) India’s first self launched satellite was

a) IRS (b) Aryabhat (c) Rohini (d) INSAT.

Ans: – Option(b).

(iii) For the same velocity, will a higher frequency of a sound wave mean

(a) Higher wavelength

(b) Lower wavelength

(c) The same wavelength.

Ans: – Option(i).

(iv) Sound travels fastest in

a) Solid (b) Liquid (c) Gas.

Ans: – Option(a).

(v) The most suitable medium for RADAR would be

(a) Gas (b) Liquid (c) Solid.

Ans: – Option(a).

3) Why can’t we hear each other on Moon?

Ans: – As sound is needed a medium for the transfer so in moon there is no air so sounds don’t travel.

4) Describe 2 experiments to show that sound has vibrations associated with it.

Ans: – (i) Aluminium hanger experiment.

(ii) Tuning fork experiment.

5) What is the relationship between velocity, wavelength and frequency?

Ans: – V=ny,

Here, v= velocity, n= frequency, y= wavelength,

6) State 3 differences between sound waves and micro waves.

Ans: –

 Sound wave Micro wave Longitudinal wave Transverse wave Travels through medium. Travels by radiation. Its travelling speed is law Its travelling speed is high.

7) What are the differences between longitudinal and transverse sound waves?

Ans: – The longitudinal wave needs medium to propagation but the transverse wave doesn’t need any types of mediums for the propagation.

8) Will sound move faster in solid or air?

Ans: – The sound speed is maximum in solid.

9) What is the basic difference between noise and music?

Ans: – The noise is produced by irregular period whereas the music is produced by regular period.

10) What makes your voice appear more musical when you sing in a bathroom?

Ans: – As when we speak out or sing a song then the period of the sound is regular in nature so its sounds seem soulful.

11) How is active SONAR different from passive SONAR?

Ans: – The basic differences between the active and passive sonar are the active sonar works like the radar which transfer the one to another and in passive sonar there is no such use of energy medium or release.

12) What are the relative merits of SONAR and RADAR? Why is it better to use SONAR in water?

Ans: – There is a benefit of using the sonar as compared to radar in the water. As the radar when transfer the signal in water its range is small because of the absorbing of the water but in sonar it doesn’t see.

13) How does SONAR help in estimating the distance of an object?

Ans: – SONAR is used for the measurements of the distance between the object which is at a place in under water by reflecting the sound wave. In this case when the sound wave is fell on the object and back to it the. Calculating the time according to distance covered we measure the existence of object under water.

Updated: February 24, 2022 — 4:57 pm