SOUND

FILL IN THE BLANKS

1. ……………. is a device that uses ultrasonic waves to measure the distance, direction and speed of underwater bodies.

2. The technique of obtaining images of internal organs of the body by using ultrasonic waves is called …………….

3. The technique of obtaining images of heart by using reflection of ultrasonic waves from various parts of heart is called …………….

4. Sound of frequency below …………… is called infrasonic sound.

5. Greater the amplitude of vibration of source the greater is …………… of sound.

MATCH THE FOLLOWING

(a) Pinna (i) 20 Hz-20 KHz

(b) Cochlea (ii) Frequency above 20 KHz

(d) Repetition of sound of a source by reflection (iv) Collects sound from surroundings

(e) Ultrasound (v) Mechanical wave

(f) Sound wave (vi) Image of heart using reflection of ultrasonic waves

(g) High frequency sound (vii) Echo

(h) Electrocardiography (viii) Converts pressure variation into electric signal

CHOOSE THE CORRECT OPTION

1.Note is a sound

(a) of mixture of several frequencies

(b) of mixture of two frequencies only

(d) always unpleasant to listen

2.Sound travels in air if

(а) particles of medium travel from one place to another

(b) there is no moisture in the atmosphere

(d) both particles as well as disturbance travel from one place to another.

3.In the curve half the wavelength is

(a) AB

(b) BD

(d) AE

4.Earthquake produces which kind of sound before the main shock wave begins

(a) ultrasound

(b) infrasound

(d) none of the above

5.Infrasound can be heard by

(a) dog

(b) bat

(d) human beings

6.In SONAR, we use

(a) ultrasonic waves

(b) infrasonic waves

(d) audible sound waves