Superposition, Stationary Waves and Beats MCQs

Question 1

Two identical waves interfere constructively. The resultant intensity is:

Accepted Answer

4 times that of one wave

Answer

zero

Answer

2 times

Answer

the same

Question 2

Noise cancellation works best for:

Accepted Answer

steady, low-frequency sounds such as engine hum

Answer

sudden, high-frequency sounds

Answer

speech only

Answer

music only

Question 3

A pipe of length 0.85 m is closed at one end (v = 340 m/s, end correction ignored). Its fundamental frequency is:

Accepted Answer

100 Hz

Answer

300 Hz

Answer

50 Hz

Answer

200 Hz

Question 4

If the anti-noise wave has a smaller amplitude than the noise, the result is:

Accepted Answer

partial cancellation (quieter noise)

Answer

complete silence

Answer

louder noise

Answer

no sound at all

Question 5

Increasing the tension in a guitar string makes its frequency:

Accepted Answer

increase

Answer

stay the same

Answer

zero

Answer

decrease

Question 6

A stationary wave does not:

Accepted Answer

transfer energy along the medium

Answer

have a frequency

Answer

have nodes

Answer

have antinodes

Question 7

When two notes are exactly in tune, the beat frequency is:

Accepted Answer

zero

Answer

infinite

Answer

equal to the note frequency

Answer

maximum

Question 8

A harbour wall gap 5 m wide is approached by sea waves of wavelength 5 m. The waves inside the harbour will:

Accepted Answer

spread out widely

Answer

double in height

Answer

stop

Answer

travel straight with no spreading

Question 9

Two coherent waves of amplitudes 6 mm and 2 mm meet. The maximum and minimum possible resultant amplitudes are:

Accepted Answer

8 mm and 4 mm

Answer

6 mm and 2 mm

Answer

12 mm and 4 mm

Answer

6.32 mm and 0 mm

Question 10

Constructive interference occurs when two waves meet:

Accepted Answer

in phase (crest on crest)

Answer

at right angles

Answer

in antiphase (crest on trough)

Answer

with different frequencies

Question 11

Two sources are coherent if they have:

Accepted Answer

the same frequency and a constant phase difference

Answer

different frequencies

Answer

the same amplitude only

Answer

random phases

Question 12

In a stretched-string experiment, increasing the frequency of the vibrator (same tension) produces:

Accepted Answer

more loops on the string

Answer

a travelling wave only

Answer

fewer loops

Answer

no change

Question 13

A closed tube resonates first at 20 cm and next at 60 cm. The wavelength is:

Accepted Answer

80 cm

Answer

40 cm

Answer

20 cm

Answer

120 cm

Question 14

Bright fringes in Young's double-slit experiment are due to:

Accepted Answer

constructive interference

Answer

polarization

Answer

destructive interference

Answer

reflection

Question 15

The distance between a node and the next antinode is:

Accepted Answer

lambda4

Answer

lambda

Answer

lambda2

Answer

2lambda

Question 16

At a point, one wave alone gives a displacement of 5 cm and another alone gives -3 cm. When both arrive, the displacement is:

Accepted Answer

2 cm

Answer

8 cm

Answer

-15 cm

Answer

5.83 cm

Question 17

All particles between two adjacent nodes of a stationary wave vibrate:

Accepted Answer

in phase with each other

Answer

with a phase difference of 90^circ

Answer

in antiphase

Answer

randomly

Question 18

Two coherent sources in phase emit waves of wavelength lambda. At a point, the path difference is 1.5lambda. The interference there is:

Accepted Answer

destructive

Answer

neither — there is no interference

Answer

constructive

Answer

constructive only for sound

Question 19

The amplitude of a stationary wave:

Accepted Answer

varies from zero at nodes to a maximum at antinodes

Answer

increases along the string

Answer

is the same everywhere

Answer

is zero everywhere

Question 20

Twice per cycle, a stretched string carrying a stationary wave is:

Accepted Answer

momentarily straight (all displacements zero)

Answer

broken

Answer

still at nodes only

Answer

at maximum displacement everywhere

Question 21

Guitar players can use 'harmonics' and beats to tune adjacent strings because:

Accepted Answer

matching harmonics give zero beats when in tune

Answer

harmonics have no frequency

Answer

harmonics are louder

Answer

beats make strings longer

Question 22

At the fixed end of a stretched string there is always:

Accepted Answer

a node

Answer

an antinode

Answer

zero tension

Answer

maximum amplitude

Question 23

Two coherent waves of amplitudes 3 mm and 5 mm meet. The maximum and minimum possible resultant amplitudes are:

Accepted Answer

8 mm and 2 mm

Answer

5 mm and 3 mm

Answer

5.83 mm and 0 mm

Answer

15 mm and 2 mm

Question 24

In a resonance tube (air column) experiment, a loud sound is heard when:

Accepted Answer

a stationary wave forms in the air column (resonance)

Answer

the tuning fork stops

Answer

the tube is empty

Answer

the water boils

Question 25

In the microwave experiment, the detector is moved along the line between transmitter and reflector. It shows:

Accepted Answer

alternating maxima (antinodes) and minima (nodes)

Answer

a constant reading

Answer

only minima

Answer

only maxima

Superposition, Stationary Waves and Beats MCQs — Physics (page 4)

76. Two identical waves interfere constructively. The resultant intensity is:

77. Noise cancellation works best for:

78. A pipe of length 0.85 m is closed at one end (v = 340 m/s, end correction ignored). Its fundamental frequency is:

79. If the anti-noise wave has a smaller amplitude than the noise, the result is:

80. Increasing the tension in a guitar string makes its frequency:

81. A stationary wave does not:

82. When two notes are exactly in tune, the beat frequency is:

83. A harbour wall gap 5 m wide is approached by sea waves of wavelength 5 m. The waves inside the harbour will:

84. Two coherent waves of amplitudes 6 mm and 2 mm meet. The maximum and minimum possible resultant amplitudes are:

85. Constructive interference occurs when two waves meet:

86. Two sources are coherent if they have:

87. In a stretched-string experiment, increasing the frequency of the vibrator (same tension) produces:

88. A closed tube resonates first at 20 cm and next at 60 cm. The wavelength is:

89. Bright fringes in Young's double-slit experiment are due to:

90. The distance between a node and the next antinode is:

91. At a point, one wave alone gives a displacement of 5 cm and another alone gives -3 cm. When both arrive, the displacement is:

92. All particles between two adjacent nodes of a stationary wave vibrate:

93. Two coherent sources in phase emit waves of wavelength lambda. At a point, the path difference is 1.5lambda. The interference there is:

94. The amplitude of a stationary wave:

95. Twice per cycle, a stretched string carrying a stationary wave is:

96. Guitar players can use 'harmonics' and beats to tune adjacent strings because:

97. At the fixed end of a stretched string there is always:

98. Two coherent waves of amplitudes 3 mm and 5 mm meet. The maximum and minimum possible resultant amplitudes are:

99. In a resonance tube (air column) experiment, a loud sound is heard when:

100. In the microwave experiment, the detector is moved along the line between transmitter and reflector. It shows:

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