Waves And Oscillation Flashcards
Define waves (3)
-an oscillation that propagates from one place to another
-they oscillate at well defined speeds determined by the property of the material
-they carry energy
State 2 types of waves (2)
-Longitudinal
-transverse
Define transverse waves (2)
-a wave in which particles oscillate perpendicular to the direction of the wave travel
-they show crest and troughs
State examples of transverse waves (2)
-light
-electromagnetic waves
Define longitudinal waves (2)
-a wave in which particles oscillate parallel to the direction of wave and energy transfer
-they show areas of compression and rarefaction
What does compression mean (1)
-areas of increased pressure and density
What does rarefaction mean (1)
-areas of decreased pressure
State examples of longitudinal waves (2)
-sound waves
-ultrasound waves
Why are longitudinal and transverse waves also called as harmonic waves (2)
-because they’re waves where the pattern of disturbance repeats regularly
What are the key features of harmonic waves (3)
-equal spacing
-regular pattern
-well defined frequency
How is energy transmitted through longitudinal waves (3)
-particles in the medium vibrate as they are given energy
-the compression causes the nearby particles to also vibrate with more energy
-this produces a compression further along the medium
Define wavelength (2)
-distance over which a wave repeats
-length of one whole cycle
Define frequency (1)
-number of vibration per unit time passing a given point
Define period (1)
-the time taken for a whole cycle to complete
Define amplitude (1)
-maximum displacement of a wave from its stationary point
State the formula of frequency (2)
F = 1/ period
F = speed of wave / wavelength
State the formula for speed of wave (1)
Speed of wave = distance / time
What is the speed of sound in air under normal ATM and temperature (1)
V = 343m/s
How is speed determined in solids (1)
-the stiffer the material, the faster the sound wave is
(Sometimes to calculate speed of sound you may have to use Kinematics equations)
You drop a stone from rest into a well that is 7.35m deep. How long does it take before you hear a splash (3)
Distance = UT + 1/2at^2
7.35 = 0xt + 1/2x9.81xt2
T= 1.22
Distance = velocity x time
7.35/343
T = 0.0214s
T = T1 + T2
0.0214 + 1.22
=1.24s
How is the pitch of sound determined (1)
By frequency
What is the range of pitch humans can hear (1)
20Hz - 20,000Hz
Define ultrasonic (1)
Sounds with the frequencies above the human hearing range
Define infrasonic (1)
Sounds with frequencies below the human hearing range