Sound Class 9 Test

                  Spectrum Classes
Test Topic : Sound Class IX
Time: 1:30 hrs Max Marks: 40
Note : MCQ’s  are of 1 marks each .
1. Wavelength of sound wave has units :-
(a) metres (b) metres/sound (c) (metres)2 (d) meters/second2        
2. Light is a (a) Longitudinal wave (b) Transverse wave (c) Both (d) None
3. In compression, pressure density is
(a) High (b) Less (c) Remains same (d) May be a) or b) depending upon disturbance
4. Frequency of ultrasonic sound wave is
(a) Greater than 20 HZ (b) Greater than 20,000 HZ (c) Greater than 2 HZ (d) Greater than 2 MHZ
5. A sound wave travels from east to west, in which direction do the particles of air move?
(A) East – west  (B) North - south  (C) Up and down      (D) None of these
6. In which medium sound travels faster ?
(A) Solid      (B) Liquid (C) Gas   (D) None of these
7. What is the name of short duration wave? (A) Pulse (B) Frequency(C) Time period(D) Velocity
8. What is the velocity of sound in water at room temperature?
(A) 1500 m/s     (B) 330 m/s (C) 1500 km/s                 (D) 330 km/s
9. The unit of quantity on which pitch of the sound depends is :
(A) Hertz    (B) metre  (C) metre/second    (D) second
10. The unit of quantity on which loudness of found depends is :
(A) metre           (B) Hertz                (C) metre/second       (D) second
11. Nature of sound wave is :
(A) transverse        (B) longitudinal      (C) electromagnetic         (D) seismic
11. Pitch of high frequency sound is :
(A) high    (B) low      (C) zero     (D) infinite
12. Voice of a friend is recognized by its :
(A) Pitch       (B) quality         (C) Intensity      (D) velocity                                             
13. Sound waves in air are : (A) Longitudinal waves (B) Radio waves(C) Transverse waves(D) Electromagnetic waves
14.Difference between Travel and propagate is ………………………………..
15. Differentiate between longitudinal and transverse wave? [2]
16. Define the terms:- 1) Wavelength 2) Frequency        [2]
17. An underwater device directs ultrasounds of frequency 75 KHZ towards water surface. What is the wavelength of sound in the air above the water surface and what is its frequency? Speed of sound in air = 340m/s.            [2]
18. What is an echo? Name two areas of its application?             [2]
19. What happens when sound travels in air?                                 [3]
20. Establish the relation for a wave that velocity = frequency X wavelength.       [3]
21. When a wave travels from one medium to another, the wavelength changes but
not the frequency. The wavelength of sound disturbance 30 cm in air and of the
wave velocity is 340 m/s. What will be the wavelength of this disturbance in
Helium & water? The speed of sound in helium is 970 m/s and 1450 m/s in water?     [3]
22. Sound waves of wavelength λ travel from a medium in which its velocity is v m/s
into another medium in which if velocity is 3 v m/s. What is the wavelength of the
sound λ in the second medium [3]
23.Explain working of Sonar with diagram .[3]
24.Explain working of Human ear with diagram .[3]
Er.Shyam Pachori
CL 157 D.D Nagar Gwalior
Mob.: 9039803981