AP ECET PHYSICS Multiple Choice Questions (MCQs)

91. Which of the following is the primary difference between musical sound and noise?

• A) Musical sound has irregular waveforms, while noise has regular waveforms.
• B) Musical sound has a definite frequency, while noise has an irregular frequency.
• C) Noise is always louder than musical sound.
• D) Musical sound has a high amplitude, while noise has low amplitude.

Answer: B) Musical sound has a definite frequency, while noise has an irregular frequency.

92. Noise pollution is primarily caused by:

• A) Sound from natural sources like waterfalls.
• B) Sound emitted from high-speed trains.
• C) Sound produced by musical instruments.
• D) The movement of ocean currents.

Answer: B) Sound emitted from high-speed trains.

93. Which of the following is a potential effect of prolonged exposure to noise pollution?

• A) Increased concentration.
• B) Improved sleep quality.
• C) Hearing impairment.
• D) Increased ability to focus.

Answer: C) Hearing impairment.

94. Which of the following methods can help in controlling noise pollution?

• A) Increasing vehicle speed limits.
• B) Using noise barriers in construction.
• C) Playing loud music in public spaces.
• D) Reducing public awareness about noise pollution.

Answer: B) Using noise barriers in construction.

95. Beats are produced when two sound waves of slightly different frequencies:

• A) Travel in opposite directions.
• B) Combine to produce a high-pitched sound.
• C) Interfere with each other.
• D) Cancel each other out.

Answer: C) Interfere with each other.

96. The phenomenon of an echo is most commonly observed in:

• A) A stadium.
• B) A busy road.
• C) A dense forest.
• D) An open field.

Answer: A) A stadium.

97. The Doppler effect is the change in frequency or wavelength of a wave in relation to:

• A) The medium of propagation.
• B) The observer and the source of the wave.
• C) The amplitude of the wave.
• D) The type of wave.

Answer: B) The observer and the source of the wave.

98. The Doppler effect can be observed when:

• A) A car passes by with its horn sounding.
• B) A bird sings in a forest.
• C) A person speaks in a quiet room.
• D) A bell rings continuously.

Answer: A) A car passes by with its horn sounding.

99. The frequency of the sound heard by the observer in the Doppler effect depends on:

• A) The speed of the observer only.
• B) The speed of sound only.
• C) The relative motion between the source and observer.
• D) The medium through which the sound is transmitted.

Answer: C) The relative motion between the source and observer.

100. The reverberation time of a building refers to:

• A) The total time taken for sound to travel across the building.
• B) The time required for a sound to decay by 60 decibels after the source stops.
• C) The time it takes for sound waves to reflect off the walls.
• D) The loudness of the sound within the building.

Answer: B) The time required for a sound to decay by 60 decibels after the source stops.

101. Sabine’s formula for reverberation time is given by:

• A) T = 4πV / A
• B) T = 0.161V / A
• C) T = 0.116V / A
• D) T = 1.42V / A

Answer: B) T = 0.161V / A

102. A good acoustic building should have:

• A) Hard, flat surfaces that reflect sound waves.
• B) Soft, irregular surfaces that absorb sound waves.
• C) Symmetrical shape and sound-proof walls.
• D) Randomly placed materials to scatter sound.

Answer: B) Soft, irregular surfaces that absorb sound waves.

103. The primary factor affecting the acoustics of a building is:

• A) The height of the building.
• B) The frequency of the sound.
• C) The shape and material of the walls and ceiling.
• D) The number of doors and windows in the building.

Answer: C) The shape and material of the walls and ceiling.

104. In acoustics, sound absorption is better when:

• A) The material is smooth and hard.
• B) The material has a low density.
• C) The material is rough and porous.
• D) The material is reflective.

Answer: C) The material is rough and porous.

105. The term “noise” refers to sound that:

• A) Is pleasant and melodious.
• B) Has no effect on the environment.
• C) Is unwanted or harmful to the environment.
• D) Travels at the speed of light.

Answer: C) Is unwanted or harmful to the environment.