NCERT Solutions for class 11 Physics | Chapter 15 - Waves
Questions
1
The extension in a string, obeying Hookes law is X. The speed of sound in the stretched string is V. If the extension in the string is increased to 1.5 X, the speed of sound will be
Answer:1.22 V
2
Four wires of identical lengths, diameters and material and stretched on a sonometer box. The ratio of their tension is 1 : 4 : 9 : 16. the ratio of their fundamental frequencies is
Answer:1 : 2 : 3 : 4
⭐ Make GKSeries Your Preferred Source on Google
Add GKSeries as Preferred Source
3
A whistle giving out 450 Hz approaches a stationary observer at a speed of 33 m/s. The frequency heard by the observer in Hz is
Answer:500
4
Energy is to be carried from one place to another. Which one of the following cannot be used?
Answer:Standing (stationary) waves
5
Loudness of a note of sound is
Answer:Directly proportional to square of amplitude of wave
7
To demonstrate the phenomenon of beats we need
Answer:Two sources which emit radiation of nearly the same frequency
8
With the increase in temperature, the frequency of the sound from an organ pipe
Answer:Increases
9
A resonance air column of length 40 cm resonates with a tuning fork of frequency 450 Hz. Ignoring end correction, the velocity of sound in air will be
Answer:720 m/s
10
Transverse are generated in two uniform wires A and B by attaching their free ends to a vibrating source of frequency 600 Hz. The diameter of wire A is one-third that of wire B and tension in the wire A is double that in wire B. What is the ratio of velocities of waves of waves in wire A and B?
Answer:√2 : 3
11
String is in fundamental mode of vibration then velocity is directly proportional to _______
Answer:Square root of tension
12
With the increase in temperature, the frequency of the sound from an organ pipe
Answer:Increases
13
An observer is moving towards a stationary source of frequency 250 Hz with a velocity of 40 m/s. If the velocity of sound is 330 m/s, the apparent frequency heard by the observer will be
Answer:280 Hz
14
The frequency of the note produced by plucking a given string increases as
Answer:The tension in the string increases
15
A siren placed at a railway platfrom is emitting sound of frequency 5 kHz. A passenger sitting in a moving train A records a frequency of 5.5 kHz while the train approaches the siren. During his return journey in a different train B he records a frequency of 6.0 kHz while approaching the same siren. The ratio of velocity of train B to that of train A is
Answer:2
17
The equation of wave traveling along string is y = 3 cos p (100t – x) in C.G.S. unit then wavelength is
Answer:2 cm
18
When a compression is incident on rigid wall it is reflected as
Answer:Compression with a phase change of p
19
Water waves produced by a motorboat sailing in water are
Answer:both longitudinal and transverse
20
Sound waves of wavelength λ travelling in a medium with a speed of v m/s enter into another medium where its speed is 2v m/s. The wavelength of sound waves in the second medium is
Answer:2 λ
Chapters
- Physical World
- Units and measurements
- Motion in a straight line
- Motion in a plane
- Laws of motion
- Work energy and power
- System of particles and rotational motion
- Gravitation
- Mechanical properties of solids
- Mechanical properties of fluids
- Thermal properties of matter
- thermodynamics
- Kinetic theory
- Oscillations
- Waves
