Transverse & Longitudinal Waves Flashcards
What is a transverse wave?
A wave in which the particles oscillate perpendicular to the direction of the of wave travel & energy transfer.
Examples of transverse waves.
Electromagnetic waves or vibrations on a guitar string.
Which waves can be polarised?
Transverse waves.
What is a longitudinal wave?
A wave in which the particles oscillate parallel to the direction of energy transfer & wave travel.
Examples of longitudinal waves?
Sound waves, ultrasound waves.
What is displacement of a wave?
The distance of a point on a wave from its equilibrium position.
What is the amplitude of a wave?
The maximum displacement of a particle from ts equilibrium position.
What is wavelength?
The distance between points on successive oscillations of the wave that are in phase.
What is the time period of a wave?
The time taken to complete one complete oscillation or cycle of a wave.
What is wave frequency?
The number of complete oscillations or wavelengths passing a point per unit time.
What is wave speed?
The distance travelled by the wave per unit time, defined by the wave equation.
What is phase difference?
How far the cycle of one point is compared to another point on the same wave.
When are waves in phase?
When their crests or troughs align for waves of the same frequency.
When are waves in antiphase?
When the crest of one wave aligns with the trough of another for waves of the same frequency.
What is the equation for frequency?
F=1/T
Where T is time period.
How to determine frequency of a wave?
Use a cathode-ray oscilloscope; (a lab instrument used to display,measure and analyse waveforms of electrical circuits)
X-axis is voltage and y-axis is the time base (how many seconds each division represents).
Divide the total number of wavelengths shown by the total time for the time period.
Then use f=1/T
(Use lots of wavelengths to reduce uncertainty)
What is the wave equation?
V=f λ
How to demonstrate waves.
Use a ripple tank full of water, a light source above and a screen below. A motorised, wooden, straight-edged bar produces plane waves and a small dipper can produce circular waves. The light shines, causing the wavefronts (crests) to be shown on the screen below.
What is intensity of a wave?
The power per unit area.
I=P/A
What is a spherical wave?
A wave from a point which spreads equally in all directions.
How does intensity link with the distance from the point on a spherical wave?
I is directly proportional to 1/r^2
Equation for intensity at surphase of a spherical wave.
I=P/(4(pi)r^2)
