# NCERT Physics Class 11 Exemplar Ch 15 Waves Part 1 (For CBSE, ICSE, IAS, NET, NRA 2022)

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## MCQ I

1. Water waves produced by a motor boat sailing in water are

(a) Neither longitudinal nor transverse.

(b) Both longitudinal and transverse.

(c) Only longitudinal.

(d) Only transverse.

Ans: (b)

2. Sound waves of wavelength travelling in a medium with a speed of enter into another medium where its speed is . Wavelength of sound waves in the second medium is

(a)

(b)

(c)

(d)

Ans: (c)

3. Speed of sound wave in air

(a) is independent of temperature.

(b) Increases with pressure.

(c) Increases with increase in humidity.

(d) Decreases with increase in humidity.

Ans: (c

4. Change in temperature of the medium changes

(a) Frequency of sound waves.

(b) Amplitude of sound waves.

(c) Wavelength of sound waves.

(d) Loudness of sound waves.

Ans: (c)

5. With propagation of longitudinal waves through a medium, the quantity transmitted is

(a) Matter.

(b) Energy.

(c) Energy and matter.

(d) Energy, matter and momentum.

Ans: (b)

6. Which of the following statements are true for wave motion?

(a) Mechanical transverse waves can propagate through all mediums.

(b) Longitudinal waves can propagate through solids only.

(c) Mechanical transverse waves can propagate through solids only.

(d) Longitudinal waves can propagate through vacuum.

Ans: (c)

7. A sound wave is passing through air column in the form of compression and rarefaction. In consecutive compressions and rarefactions,

(a) Density remains constant.

(b) Boyle՚s law is obeyed.

(c) Bulk modulus of air oscillates.

(d) There is no transfer of heat.

Ans: (d)

8. Equation of a plane progressive wave is given by . On reflection from a denser medium its amplitude becomes 2/3 of the amplitude of the incident wave. The equation of the reflected wave is

(a)

(b)

(c)

(d)

Ans: (b)

9. A string of mass 2.5 kg is under a tension of 200 N. The length of the stretched string is 20.0 m. If the transverse jerk is struck at one end of the string, the disturbance will reach the other end in

(a) one second

(b) 0.5 second

(c) 2 seconds

(d) Data given is insufficient.

Ans: (b)

10. A train whistling at constant frequency is moving towards a station at a constant speed . The train goes past a stationary observer on the station. The frequency of the sound as heard by the observer is plotted as a function of time t (Fig) . Identify the expected curve.

(a) Tital: A Train Whistling at Constant Frequency

(b) Tital: A Train Whistling at Constant Frequency

(c) Tital: A Train Whistling at Constant Frequency

(d) Tital: A Train Whistling at Constant Frequency

Ans: (c)