JEE Main Physics - Waves
Exam Duration: 60 Mins Total Questions : 30
Sound waves cannot be
- (a)
refracted
- (b)
polarised
- (c)
scattered
- (d)
used to produce hologram
In a stationary waves,
- (a)
the energy of the waves is zero
- (b)
the energy in the medium is zero
- (c)
the energy transfer in the direction of propagation is zero
- (d)
the energy density of the waves is constant
A wave is reflected normally from the surface of a denser medium back into the rarer medium. The phase of the wave caused by reflection will differ by
- (a)
a quarter cycle
- (b)
a half cycle
- (c)
a cycle
- (d)
a three-fourth of a cycle
A pulse along a stretched string travels at a speed of 5 ms-1 and frequency of 20 Hz. What is the phase difference in radians between two points situated 2.5 am apart?
- (a)
\(\pi /4\)
- (b)
\(\pi /5\)
- (c)
\(\pi /6\)
- (d)
\(\pi /8\)
A wave is represented by the equation
\(y\quad =\quad a\quad sin\quad (\omega t\quad -\quad kx)\)
The maximum particle velocity will be four times wave velocity if ak is equal to
- (a)
1
- (b)
2
- (c)
3
- (d)
4
When the stationary waves are set up,
- (a)
all the particles of the medium execute simple harmonic motion
- (b)
all the particles of the medium have the same maximum velocity
- (c)
all the particles between two consecutive nodes are those between the next two nodes are in the same phase
- (d)
all the particles between two consecutive nodes are out of phase from the particles between the next two nodes
Two sound waves of the same frequency have respective amplitudes of 3 units and 1 unit and are travelling in opposite directions in the same straight line. At a particular place in that line, the resultant wave will vary in loudness. The ratio of maximum loudness to minimum loudness is
- (a)
9 : 1
- (b)
6 : 1
- (c)
9 : 2
- (d)
4 : 1
A train moving away from a cliff whistles when at a distance of 300 m from it an echo is heard by the driver in 2s. The speed of the train in km h-1 is
- (a)
30
- (b)
108
- (c)
648
- (d)
660
The velocity of sound in carbon dioxide is less than in hydrogen because
- (a)
carbon dioxide has more degrees of freedom
- (b)
carbon dioxide is soluble in water
- (c)
carbon dioxide is heavier than hydrogen
- (d)
carbon dioxide is a compound and hydrogen is an element
Two travelling waves of sound are found to have sinusoidal waveform but different wavelength and different amplitude. They will have
- (a)
same pitch but different intensity
- (b)
same pitch but different quality
- (c)
same quality but different intensity
- (d)
different quality and intensity
I organic pipe (or in the resonance apparatus) we have the formation of
- (a)
stationary transverse waves
- (b)
stationary longitudinal waves
- (c)
progressive longitudinal waves
- (d)
progressive transverse waves
A tuning fork is an octave to an organ pipe. It can sound only with
- (a)
a closed pipe
- (b)
an open pipe
- (c)
both open and closed pipes
- (d)
NONE OF THE ABOVE
At a point 20 m from a small sources of sound, the density is \(0.5\quad \mu W\quad { cm }^{ 2 }\). The rate of emission of sound energy from the source is
- (a)
25 W
- (b)
\(0.5\quad \mu W\)
- (c)
\(25\quad \mu W\)
- (d)
25 mV
A pipe closed at one end resonates to its fundamental frequency of 800 Hz. Which frequencies from A, B, C and D can the pipe also resonate to?
A. 1600 Hz B. 2400 Hz C. 3200 Hz D. 4000 Hz
- (a)
if A and B are correct
- (b)
if B and C are correct
- (c)
if B and C are correct
- (d)
if A, B, C and D are correct
A simple harmonic wave propagates in the positive x-direction along a taut string that has a tension of T = 100 N. The equation of the wave function is \(y(x,\quad t)\quad =\quad 0.05\quad cos\quad 2\pi \left( \frac { x }{ 0.75 } -188.5t \right) \) in metres
The average power transmitted along the string is
- (a)
1.24 kW
- (b)
1.24 W
- (c)
1.24 X 105 N
- (d)
NONE OF THESE
A simple harmonic wave propagates along a taut string. The wavelength of the wave is 0.75 m and its time period is 5.30 ms. The average power transmitted along the string is 1.24 kW, then the total energy per wavelength in the wave is
- (a)
6.57 J
- (b)
0.23 X 106 J
- (c)
1.55 X 103 J
- (d)
NONE OF THE ABOVE
A thin aluminium rod (diameter = 1 mm) is very long and is under a uniform tension of 1000 N. Its Young's modulus (Y) is 7.0 X 1010 Pa and its density \((\rho )\) is 2.70 g cm-3. The velocity of transverse waves on the rod is
- (a)
5092 ms-1
- (b)
equal to that longitudinal waves and it is 5092 ms-1
- (c)
686.7 ms-1 and it is also that of longitudinal waves
- (d)
68607 ms-1
By using special laboratory apparataus, it is possible to produce sound waves with wavelength in air as small as, comparable with wavelength of
- (a)
infrared light
- (b)
visible light
- (c)
ultraviolet light
- (d)
x-rays
The change in the temperature affects which of the following factors for sound wave
- (a)
wavelength
- (b)
amplitude
- (c)
frequency
- (d)
intensity
The sonometer wire is vibrating in the second overtone. We may say that there are
- (a)
two nodes and two antinodes
- (b)
one node ant two antinodes
- (c)
four nodes and three antinodes
- (d)
three nodes and three antinodes
A wave of frequency 100 Hz travels along a string towards its fixed end. When this wave travels back, after reflection, a node is formed at a distance 10 cm from the fixed end. The speed of the wave (reflected and incident) is
- (a)
5 ms-1
- (b)
2.0 ms-1
- (c)
100 ms-1
- (d)
40 ms-1
A stationary wave is represented by
y = A sin (100 t) cos (0.01 x)
where A and y are in mm t in seconds and x metre. The velocity of the wave is
- (a)
1 ms-1
- (b)
100 ms-1
- (c)
104 ms-1
- (d)
not derivable from the given data
Which of the following does not represent a wave?
- (a)
\(y\quad =\quad a\quad sin\quad (\omega t-kx)\)
- (b)
y = a cos kx
- (c)
\(y\quad =\quad a\quad sin\quad \omega t\)
- (d)
y = a sin (at - bx + c)
A simple rod clamped in the middle can be set into longitudinal vibration. What kind of vibrations does it produce when bent to form a turning fork?
- (a)
Transverse
- (b)
Longitudinal
- (c)
Both transverse and longitudinal
- (d)
Transverse or longitudinal depending upon the medium
The equation
\(\vec { \varphi } (x,t)\quad =\quad \vec { j } \quad sin\quad \left( \frac { 2\pi Vt }{ \lambda } \right) \quad cos\quad \left( \frac { 2\pi x }{ \lambda } \right) \) represents a
- (a)
transverse progressive wave
- (b)
longitudinal progressive wave
- (c)
lomgitudinal stationary wave
- (d)
transverse stationary wave
A standing wave having 3 nodes and 2 antinodes is formed between two atoms having a distance \(1.21 ?\) between them. The wavelength of standing wave is
- (a)
\(1.21\)
- (b)
\(2.42\)
- (c)
\(6.05\)
- (d)
\(3.63\)
A sonometer wire resonates with a given tunning fork forming standing waves with five antinodes between the two bridges when a mass is replaced by a mass M, the wire resonates with the same tuning fork forming three antinodes for the same positions of the bridges. The value of M is
- (a)
25 kg
- (b)
5 kg
- (c)
12.5 kg
- (d)
1/25 kg