33 Years NEET-AIPMT Chapterwise Solutions - Physics 2020

Waves
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115
CHAPTER
15
Waves
15.2 Transverse and Longitudinal Waves
1. Which one of the following statements is true?
(a) Both light and sound waves can travel in vacuum.
(b) Both light and sound waves in air are transverse.
(c) The sound waves in air are longitudinal while
the light waves are transverse.
(d) Both light and sound waves in air are
longitudinal. (2006)
2. With the propagation of a longitudinal wave through
a material medium, the quantities transmitted in the
propagation direction are
(a) energy, momentum and mass
(b) energy
(c) energy and mass
(d) energy and linear momentum (1992)
15.3 Displacement Relation in a Progressive
Wave
3. A wave travelling in the +ve x-direction having
displacement along y-direction as 1 m, wavelength
2p m and frequency of 1 Hz is represented by
π
(a) y = sin(10px – 20pt)
(b) y = sin(2px + 2pt)
(c) y = sin(x – 2t)
(d) y = sin(2px – 2pt) (NEET 2013)
4. Two waves are represented by the equations
y 1 = asin(wt + kx + 0.57) m and
y 2 = acos(wt + kx) m, where x is in meter and t in
sec. The phase difference between them is
(a) 1.0 radian (b) 1.25 radian
(c) 1.57 radian (d) 0.57 radian (2011)
5. A wave in a string has an amplitude of
2 cm. The wave travels in the +ve direction of x
axis with a speed of 128 m/s and it is noted that 5
complete waves fit in 4 m length of the string. The
equation describing the wave is
(a) y = (0.02) m sin (15.7 x – 2010t)
(b) y = (0.02) m sin (15.7 x + 2010t)
(c) y = (0.02) m sin (7.85x – 1005t)
(d) y = (0.02) m sin (7.85x + 1005t) (2009)
6. The wave described by y = 0.25 sin (10px – 2pt),
where x and y are in meters and t in seconds, is a
wave travelling along the
(a) +ve x direction with frequency 1 Hz and
wavelength l = 0.2 m.
(b) –ve x direction with amplitude 0.25 m and
wavelength l = 0.2 m.
(c) –ve x direction with frequency 1 Hz.
(d) +ve x direction with frequency p Hz and
wavelength l = 0.2 m (2008)
7. The phase difference between two waves, represented
by
y 1 = 10 –6 sin[100t + (x/50) + 0.5] m
y 2 = 10 –6 cos[100t + (x/50)] m,
where x is expressed in metres and t is expressed in
seconds, is approximately
(a) 1.07 radians (b) 2.07 radians
(c) 0.5 radians (d) 1.5 radians
(2004)
8. A wave travelling in positive X-direction with
a = 0.2 m s –2 , velocity = 360 m s –1 and l = 60 m, then
correct expression for the wave is
⎡ ⎛ x ⎞⎤
(a) y= 02 . sin ⎢2π
t+
⎝
⎜6
⎠
⎟⎥
⎣ 60 ⎦
⎡ ⎛ x ⎞⎤
(b) y= 02 . sin ⎢π
t+
⎝
⎜6
⎠
⎟⎥
⎣ 60 ⎦
⎡ ⎛ x ⎞⎤
(c) y= 02 . sin ⎢2π
t−
⎝
⎜6
⎠
⎟⎥
⎣ 60 ⎦
⎡ ⎛ x ⎞⎤
(d) y= 02 . sin ⎢π t−
⎝
⎜6
⎠
⎟⎥
⎣ 60 ⎦
(2002)
9. In a sinusoidal wave, the time required for
a particular point to move from maximum
displacement to zero displacement is
0.170 s. The frequency of wave is
(a) 0.73 Hz (b) 0.36 Hz
(c) 1.47 Hz (d) 2.94 Hz (1998)