# Topic: UNIT XI: Waves (Test 1)

Topic: UNIT XI: Waves
Q.1
A student tunes his guitar by striking a 120 Hertz with a tuning fork, and simultaneously plays the 4th string on his guitar. By keen observation, he hears the amplitude of the combined sound oscillating thrice per second. Which of the following frequencies is the most likely the frequency of the 4th string on his guitar?.
A. 130
B. 117
C. 110
D. 120
Explaination / Solution:
No Explaination.

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Q.2
A transverse wave moves from a medium A to a medium B. In medium A, the velocity of the transverse wave is 500 ms-1 and the wavelength is 5 m. The frequency and the wavelength of the wave in medium B when its velocity is 600 ms-1, respectively are
A. 120 Hz and 5 m
B. 100 Hz and 5 m
C. 120 Hz and 6 m
D. 100 Hz and 6 m
Explaination / Solution:
No Explaination.

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Q.3
For a particular tube, among six harmonic frequencies below 1000 Hz, only four harmonic frequencies are given : 300 Hz, 600 Hz, 750 Hz and 900 Hz. What are the two other frequencies missing from this list?.
A. 100 Hz, 150 Hz
B. 150 Hz, 450 Hz
C. 450 Hz, 700 Hz
D. 700 Hz, 800 Hz
Explaination / Solution:
No Explaination.

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Q.4

Which of the following options is correct?. Options for (1), (2) and (3), respectively are
A. (B),(C) and (A)
B. (C), (A) and (B)
C. (A), (B) and (C)
D. (B), (A) and (C)
Explaination / Solution:
No Explaination.

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Q.5

Compare the velocities of the wave forms given below, and choose the correct option. where, vA, vB, vC and vD are velocities given in (A), (B), (C) and (D), respectively.
A. vA > vB > vD > vC
B. vA< vB < vD < vC
C. vA = vB = vD = vC
D. vA > vB = vD > vC
Explaination / Solution:
No Explaination.

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Q.6
A sound wave whose frequency is 5000 Hz travels in air and then hits the water surface. The ratio of its wavelengths in water and air is
A. 4.30
B. 0.23
C. 5.30
D. 1.23
Explaination / Solution:
No Explaination.

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Q.7
A person standing between two parallel hills fires a gun and hears the first echo after t1 sec and the second echo after t2 sec. The distance between the two hills is
A. B. C. D. Explaination / Solution:
No Explaination.

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Q.8
An air column in a pipe which is closed at one end, will be in resonance with the vibrating body of frequency 83Hz. Then the length of the air column is
A. 1.5 m
B. 0.5 m
C. 1.0 m
D. 2.0 m
Explaination / Solution:
No Explaination.

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Q.9
The displacement y of a wave travelling in the x direction is given by y = (2x10-3) sin(300t-2x+π/4), where x and y are measured in metres and t in second. The speed of the wave is
A. 150 ms-1
B. 300 ms-1
C. 450 ms-1
D. 600 ms-1
Explaination / Solution:
No Explaination.

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Q.10
Consider two uniform wires vibrating simultaneously in their fundamental notes. The tensions, densities, lengths and diameter of the two wires are in the ratio 8 : 1, 1 : 2, x : y and 4 : 1 respectively. If the note of the higher pitch has a frequency of 360 Hz and the number of beats produced per second is 10, then the value of x : y is
A. 36 : 35
B. 35 : 36
C. 1 : 1
D. 1 : 2