11.sound Flashcards
Longitudinal Waves
Direction: Particles vibrate parallel to the wave’s propagation.
Examples:
Sound waves
Seismic P-waves
Medium: Requires a medium Longitudinal Waves
Key Feature: Compression and rarefaction.
Transverse Waves
Direction: Particles vibrate perpendicular to the wave’s propagation.
Examples:
Water surface waves
Seismic S-waves
Medium: Can travel in solids or at surfaces (e.g., water).
Key Feature: Crests and troughs.
Wavelength
The distance between two consecutive
compressions (C) or two consecutive
rarefactions (R) is called the wavelength
The wavelength is
usually represented by λ (Greek letter
lambda). Its SI unit is metre (m).
Frequency
Frequency is the number of complete oscillations or cycles of a wave that occur in a unit of time, typically measured in hertz (Hz). One hertz equals one cycle per second.
pitch
How the brain interprets the frequency
of an emitted sound is called its pitch
The loudness or softness of a sound is
determined basically by its
amplitute
amplitude
The magnitude of the maximum
disturbance in the medium on either side of
the mean value is called the amplitude of the
wave
the speed of sound in air is 331
m s–1 at 0ºCd 344 m s–1 at 22 ºC
speed of sound —— from solid to gas
decrease
The speed of sound in a medium depends on
temperature and medium
speed of sound ____with temperature
increase
To hear a distinct echo the time interval
between the original sound and the
reflected one must be at
least 0.1s
USES OF MULTIPLE REFLECTION
OF SOUND
Megaphones or loudhailers, horns,
musical instruments such as trumpets
and shehanais,
The audible range of sound for human beings
extends from about
20 Hz to 20000 Hz (one
Hz = one cycle/s
Children under the age of
five and some animals, such as dogs can hear
up to
25 kHz (1 kHz = 1000 Hz)
Whales and
elephants produce sound in the
infrasound
range
Rhinoceroses communicate using infrasound
of frequency as low as
5 Hz
. Frequencies higher than 20 kHz
are called
ultrasonic sound or ultrasound
Ultrasound is produced by animals such as
dolphins, bats and porpoises.
uses of ultrasound
Medical: For imaging (e.g., pregnancy scans), diagnosing organ conditions, and guiding procedures.
Industrial: For non-destructive testing of materials and cleaning delicate items.
Veterinary: Used to monitor animal health and pregnancies.
Navigation: In sonar systems for underwater detection.
Pest Control: To repel rodents and insects with high-frequency sound
Ultrasonic waves are made to reflect
from various parts of the heart and
form the image of the heart
‘echocardiography
These waves are then converted into
electrical signals that are used to
generate images of the organ. These
images are then displayed on a monitor
or printed on a film. This technique
is called
ultrasonography
SONAR
(Sound Navigation and Ranging) is a technology that uses sound waves to detect and locate objects underwater. It works by emitting sound waves and measuring how long it takes for them to bounce back (echo) after hitting an object.
Sound waves are:
(a) Transverse waves
(b) Longitudinal waves
(c) Electromagnetic waves
(d) None of the above
(b) Longitudinal waves
The speed of sound is highest in:
(a) Air
(b) Water
(c) Steel
(d) Vacuum
(c) Steel
The principle of SONAR is based on:
(a) Doppler Effect
(b) Reflection of sound waves
(c) Refraction of sound waves
(d) Diffraction of sound waves
(b) Reflection of sound waves
Which of the following frequencies is within the audible range for humans?
(a) 10 Hz
(b) 50,000 Hz
(c) 5,000 Hz
(d) 1,50,000 Hz
(c) 5,000 Hz
The phenomenon of the change in frequency of sound due to relative motion between the source and observer is called:
(a) Resonance
(b) Interference
(c) Doppler Effect
(d) Diffraction
(c) Doppler Effect
