Module1.1 Flashcards
What is a wave?
A disturbance away from the average condition
When does wave imply?
When something changes in a periodic or regular manner
What changes in corrugated iron as we move along the sheet?
Physical shape and orientation of the metal changes its position in space
What changes in the case of pendulum?
Position of the arm in time
What is A in p=A sin(2ㅠx/ㅅ)?
Amplitude
What is ㅅ in p=A sin(2ㅠx/ㅅ)?
Wavelength
What is p in p=A sin(2ㅠx/ㅅ)?
Disturbance or variation
What symbolises
- frequency
- angular frequency
- Period
f
W
T
What is wave speed
Represented by c
Has unit of metre per sec (m/s)
Speed at which energy is transported by the wave
What is velocity
Is to specify the wave speed and the direction in which the wave is travelling /vector quantity
Air exerts () on us
Force
Force/area differ?
What is force/area?
No constant
Pressure
Units of pressure?
Pa (1Pa=N/m^2)
What is p0
Ambient pressure (average)
What does p>p0 mean?
The fluid is compressed
What is p
The fluid is rarefied
What is general term for amplitude?
Magnitude
What is the maximum excursion of an atom from its average position
Displacement
What is related to the square of the pressure amplitude but depends on the frequency as well? (Almost zero)
Loudness
What is the energy carried by the wave covering some specified area in a specified time.
Intensity
How do u measure the intensity?
Watts per area OR mW/cm^2
What is the energy content of the beam per second?
Power
Whats the unit of power
Watt =J/s
What is an average wave speed?
1540m/s =c
What is the atom or the molecules that comprise the material that are vibrating about their average position called?
Particle
What is it called when the sinusoidal motion of the particles have a speed and varies in a sinusoidal
Fashion
Particle speed
What is it called when the particles move perpendicular to the direction of wave?
Transverse wave
What is it called when the particle vibrate in the direction that is at all times parallel or anti parallel to the wAve direction?
Longitudinal wave
What is a line drawn to show the direction the wave is traveling?
Ray
What is the representiation of the crests at some instant of time?
Wavefronts
Who recognized that the wavefront in those cases where the source of the wave was extended could be determined by imagining that an extended source could be viewed as a series of point sources each generating wavefronts?
Christiaan huygens
What is the circular or spherical source about one wave length apart and joining up the tangents to these elementary wavefronts?
Huygens’ wavelets
Whats called when two waves of the same frequency exist in the same region of the material?
Interfere
When two waves of the same frequency interfere, what happens?
Constructive/destructive
What happen to two waves having amplitude A meet constructively?
Amplitude become 2A
What happen to the power of 2 waves of same amplitude A when they meet? (Total constructive case)
4 since power and intensity is proportional to the square of the amplitude
What is called when generally two or more waves meet and simply add up the mathematical expressions for the individual waves taking into account the relative travelling wave direction?
Superposition
