The loudness of sound depends upon the
- A.velocity of sound waves in the medium.
- B.amplitude of the sound waves.
- C.frequency of the sound waves.
- D.frequency and velocity of the sound waves.
Correct answer
Explanation
The correct answer is B, the amplitude of the sound waves. Amplitude is the maximum displacement of a particle of the medium from its rest position, and the energy carried by a wave increases with the square of the amplitude. A larger amplitude therefore delivers more energy to the ear and is heard as a louder sound. Loudness is measured in decibel.
Option A, the velocity of the wave, is fixed by the medium and its temperature; a loud and a soft sound in the same room travel at exactly the same speed. Option C, frequency, decides pitch, that is whether the sound is shrill or flat, and not how loud it is; turning up the volume of a ringtone does not change its frequency. Option D combines two quantities that both govern properties other than loudness, so it is wrong for the same reasons.
Read the full article: Sound and Waves: Properties, Speed and PYQs
Practice Questions
View allThe frequency of a sound wave is 50 Hz and its wavelength is 4 m. What is the distance travelled by the sound wave in 3 s?
- A.100 m
- B.600 m
- C.200 m
- D.300 m
Show answer
The speed of a wave is the product of its frequency and its wavelength, so the speed here is 50 hertz multiplied by 4 metres, that is 200 metres per second.
Read the full explanation →The brain interprets the frequency of an emitted sound called -
- A.Wavelength
- B.Wave velocity
- C.Pitch
- D.Oscillation
Show answer
Pitch is the characteristic of a sound by which the brain judges it as shrill or flat, and it is decided by the frequency of the wave.
Read the full explanation →A sound wave has a frequency of 1 kHz and wavelength 50 cm. How long will it take to travel 1 km?
- A.5 s
- B.4 s
- C.3 s
- D.2 s
Show answer
Convert the units first: 1 kilohertz is 1000 hertz and 50 centimetres is 0.5 metre. The speed is frequency multiplied by wavelength, that is 1000 multiplied by 0.5, which gives 500 metres per second.
Read the full explanation →The flash of lightning is seen before the thunderstorm is heard. It verifies that
- A.sound travels much faster than light
- B.light travels much faster than sound
- C.light and sound both travel with same speed
- D.intensity of flash of lightning is very high during thunderstorm
Show answer
The flash and the clap are produced at the same instant by the same discharge.
Read the full explanation →Sound waves are:
- A.Transverse electromagnetic waves
- B.Longitudinal mechanical waves
- C.Transverse mechanical waves only in solids
- D.Waves that need no medium to travel
Show answer
In a sound wave the particles of the medium vibrate back and forth along the same line in which the wave is travelling, producing regions where they crowd together, called compressions, and regions where they spread apart, called rarefactions.
Read the full explanation →