33 Years NEET-AIPMT Chapterwise Solutions - Physics 2020

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116 NEET-AIPMT Chapterwise Topicwise Solutions Physics
10. The equation of a sound wave is
y = 0.0015 sin (62.4x + 316t).
The wavelength of this wave is
(a) 0.3 unit (b) 0.2 unit
(c) 0.1 unit
(d) cannot be calculated. (1996)
11. Two sound waves having a phase difference of 60°
have path difference of (l is wavelength of sound
wave)
(a)
λ
6
(b)
λ
3
(c) 2l (d) λ 2 (1996)
12. Which one of the following represents a wave?
(a) y = Asin (wt – kx)
(b) y = Acos(at – bx + c)
(c) y = Asinkx
(d) y = Asinwt. (1994)
13. The frequency of sinusodial wave
y = 0.40cos [2000 t + 0.80] would be
(a) 1000p Hz (b) 2000 Hz
(c) 20 Hz (d) 1000
π Hz (1992)
14. Equation of progressive wave is given by
⎡ ⎛ t x⎞
y = ⎢ −
⎝
⎜
⎠
⎟
⎣
+ π⎤
4sin π
5 9 6
⎥ where y, x are in cm and t is
⎦
in seconds. Then which of the following is correct ?
(a) v = 5 cm (b) l = 18 cm
(c) a = 0.04 cm (d) f = 50 Hz (1988)
15.4 The Speed of a Travelling Wave
15. A uniform rope of length L and mass m 1 hangs
vertically from a rigid support. A block of mass m 2
is attached to the free end of the rope. A transverse
pulse of wavelength l 1 is produced at the lower end
of the rope. The wavelength of the pulse when it
reaches the top of the rope is l 2 . The ratio l 2 /l 1 is
(a)
m2
m1
(b)
m1 + m2
m1
m
(c) 1
m
(d)
1 + m2
m2
m2
(NEET-I 2016)
16. 4.0 g of a gas occupies 22.4 litres at NTP. The specific
heat capacity of the gas at constant volume is
5.0 J K –1 mol –1 . If the speed of sound in this gas at
NTP is 952 m s –1 , then the heat capacity at constant
pressure is (Take gas constant R = 8.3 J K –1 mol –1 )
(a) 7.0 J K –1 mol –1 (b) 8.5 J K –1 mol –1
(c) 8.0 J K –1 mol –1 (d) 7.5 J K –1 mol –1 (2015)
17. The equation of a simple harmonic wave is given by
y = 3 sin π ( t−
x
2 50 ),
where x and y are in metres and t is in seconds.
The ratio of maximum particle velocity to the wave
velocity is
(a) 2p (b)
3
2 π (c) 3p (d) 2 3 π
(Mains 2012)
18. Sound waves travel at 350 m/s through a warm air
and at 3500 m/s through brass. The wavelength of a
700 Hz acoustic wave as it enters brass from warm
air
(a) decrease by a factor 10
(b) increase by a factor 20
(c) increase by a factor 10
(d) decrease by a factor 20 (2011)
19. A transverse wave is represented by
y = Asin(wt – kx). For what value of the wavelength
is the wave velocity equal to the maximum particle
velocity?
(a) pA/2
(b) pA
(c) 2pA (d) A (2010)
20. A transverse wave propagating along x-axis is
represented by y(x, t) = 8.0sin(0.5px – 4pt – p/4)
where x is in metres and t is in seconds. The speed of
the wave is
(a) 8 m/s
(b) 4p m/s
(c) 0.5p m/s (d) p/4 m/s. (2006)
21. A point source emits sound equally in all directions
in a non-absorbing medium. Two points P and Q are
at distances of 2 m and 3 m respectively from the
source. The ratio of the intensities of the waves at P and
Q is
(a) 3 : 2 (b) 2 : 3
(c) 9 : 4 (d) 4 : 9. (2005)
22. The equation of a wave is represented by
y = 10 –4 ⎛ x ⎞
sin 100t
−
⎝
⎜
10 ⎠
⎟ m, then the velocity of wave
will be
(a) 100 m/s (b) 4 m/s
(c) 1000 m/s (d) 10 m/s (2001)
23. A transverse wave is represented by the equation
2π
y= y0
sin ( vt −x)
λ
For what value of l, is the maximum particle velocity
equal to two times the wave velocity?
(a) λ = πy
0 (b) λ = πy
0
2
3
(c) l = 2py 0 (d) l = py 0 (1998)