Physics - Wave Motion
Exam Duration: 45 Mins Total Questions : 25
Tw3o copper wire of radius R1 and R2 are such that R1>R2.Then, which of the following is true?
- (a)
Transverse wave travels faster in thinner wire
- (b)
Transverse wave travels faster in thicker wire
- (c)
Travels with same speed in both wires
- (d)
Does not travel
Two sound waves are y1=Asin(\(\omega\)t-kx) and y2=Acos(\(\omega\)t-kx).The phase difference between the two waves is
- (a)
\(\pi\)/2
- (b)
\(\pi\)/4
- (c)
\(\pi\)
- (d)
0
For stationary wave, \(y=4sin({\pi\over15})cos(96\pi t)\) Find out the distance between a node and text antinodes.
- (a)
7.5cm
- (b)
15cm
- (c)
30cm
- (d)
22.5cm
If L1 and L1 are the lengths of first and second harmonics of a resonance tube, then the wavelength of the wave is
- (a)
2(L1+L2)
- (b)
2(L2-L1)
- (c)
\(2(L_2-{L_1\over2})\)
- (d)
\(2({L_1\over2}+L_2)\)
A sonar fixed in a submarine operates at a frequency 40.0kHz.An enemy submarine moves towards the sonar with a speed of 360km/h.What is the frequency of sound reflected by the submarine?(Take the speed of sound in water to be 1450m/s)
- (a)
52.3kHz
- (b)
45.93kHz
- (c)
62.49Hz
- (d)
54.34kHz
If frequency of a tuning fork A is 2% more than frequency of standard tuning fork and tunu=ing fork B has frequency 3% less than the frequency of standard tuning fork.The frequency of same standard tuning fork, if 6 beats/s are heard, when tuning forks A and B are excited, then frequency of A is
- (a)
120Hz
- (b)
116.4Hz
- (c)
122.4Hz
- (d)
130Hz
It is possible to distinguish between transverse and longitudinal waves by studying the property of:
- (a)
interference
- (b)
diffraction
- (c)
reflection
- (d)
polarization
A light pointer fixed to one prong of a tuning fork touches a vertical plate. The fork is set vibrating and the plate is allowed to fall freely. Eight complete oscillations are counted when the plate falls through 10 em. What is the frequency of the tuning fork?
- (a)
112 Hz
- (b)
56 Hz
- (c)
8/7 Hz
- (d)
7/8 Hz
A simple harmonic wave train of amplitude 2 cm and time period 0.01 see is travelling with a velocity of 10 m/sec in the positive X-direction. The displacement of the particle from the mean position, the particle velocity and particle acceleration at x = 150 em from the origin and at t = 3 sec
- (a)
0,0,0
- (b)
0, 400π cm/sec, 0
- (c)
0,0,400π cm/sec2
- (d)
00π cm,0,0
Ultrasonic, infrasonic and audio waves travel through a medium with speed Vu ,Vi and Va respectively; then:
- (a)
Vu, Vi and Va are nearly equal
- (b)
Vu,≥ Vi ≥ Va
- (c)
Vu, ≤Vi ≤ Va
- (d)
Va≤ Vu and Vc=Vi
The velocities of sound at the same temperature in two monoatomic gases of densities ρ1 and ρ2 are v1 and v2 respectively. If ρ1/ρ2 =4, then the value of v1/v2 is:
- (a)
\(\frac{1}{4}\)
- (b)
\(\frac{1}{2}\)
- (c)
2
- (d)
4
A transverse wave is passing through a medium. The maximum speed of the vibrating particle occurs when the displacement of the particle from the mean position is:
- (a)
zero
- (b)
half of the amplitude
- (c)
equal to the amplitude
- (d)
none of these
The velocities of sound in an ideal gas at temperatures T1 and T2 K are found to be V1 and V2 respectively. If the root mean square speeds of the Game gas at the same temperatures T1, and T2 are v1, and v2 respectively, then:
- (a)
v2 =v1(V2/V1)
- (b)
v2 =v1(V1/V2)
- (c)
\({ v }_{ 2 }={ v }_{ 1 }\sqrt { { V }_{ 2 }/{ V }_{ 1 } } \)
- (d)
\({ v }_{ 2 }={ v }_{ 1 }\sqrt { { V }_{ 1 }/{ V }_{ 2 } } \)
The noise level for the threshold of pain (intensity 10° watt/m 2) is:
- (a)
10 dB
- (b)
12 dB
- (c)
120 dB
- (d)
106 dB
A travelling wave in a gas along the positive X -direction has an amplitude of 2 cm, velocity 45 m/s and frequency 75 Hz. Particle acceleration after an interval of 3 sec at a distance of 135 cm from the origin is:
- (a)
0.44 x 102crn/s2
- (b)
4.4 x 105cm/s2
- (c)
4.4 x 103cm/s2
- (d)
44 x 105 cm/s2
In a plane progressive harmonic wave particle speed is always less than the wave speed if:
- (a)
amplitude of wave<λ/2π
- (b)
amplitude of wave>λ/2π
- (c)
amplitude of wave<λ
- (d)
amplitude of wave>λ/π
The speed of sound in a mixture of 1 mole of helium and 2 moles of oxygen at 27° C is approximately:
- (a)
400 m/s
- (b)
800 m/s
- (c)
1200 m/s
- (d)
600 m/s
A tuning fork is set into vibrations and then it is held with its stem resting on a table. How will duration of its vibrations be affected?
- (a)
It will vibrate for same duration
- (b)
It will vibrate for a longer duration
- (c)
It will vibrate for a shorter duration
- (d)
The duration will increase or decrease depending upon the dimensions of the table
If sound waves can be assumed to be diffracted which of the following objects will diffract sound waves in air from a 384 Hz tuning fork?
- (a)
A sphere of radius 10 m
- (b)
A sphere of radius 1m
- (c)
A sphere of radius 1 mm
- (d)
A sphere of radius 1 cm
The disc of a siren containing 60 holes rotates at a constant speed of 360 rpm. The emitted sound is in unison with a tuning fork of frequency:
- (a)
10 Hz
- (b)
360 Hz
- (c)
216 Hz
- (d)
6 Hz
If the density of air at NTP is 1.293 kg/m 3 and ⋎=1.41then the velocity of sound in air at NTP is:
- (a)
102.3 m/s
- (b)
252.3 m/s
- (c)
332.3 m/s
- (d)
432.3 m/s
A wave travels in a medium according to the equation of displacement given by :
y(x,t)= 0.03 sin π(2t - 0.01x)
where y and x are in metre and t in second. The wavelength of the wave is:
- (a)
200 m
- (b)
100 m
- (c)
20 m
- (d)
10 m
The equation of progressive wave is y = 2sin 1t (0. 5x + 200t) (x, y in cm). The amplitude and velocity of wave respectively are:
- (a)
2πcm, 100 cm/sec
- (b)
\(\frac{2\pi}{3}\)cm, 0.5 cm/sec
- (c)
2cm, 400 cm/sec
- (d)
0.2cm, 200 cm/sec
The ratio of amplitudes of two simple harmonic motions represented by the equations Y1 = 5sin\(\left( 2\pi t+\frac { \pi }{ 4 } \right) \)Y2 = 2.√2(sin 2πt+cosπt) is
- (a)
1 : 1
- (b)
1 : 2
- (c)
5 : 2
- (d)
5 : 4
- (e)
2 : 5