(UNCOMPLETE) Wave Motion

Up to EM waves

What is a progressive wave?

An oscillation transferring energy but not matter

What are transverse + longitudinal waves?

• Transverse - oscillations are perpendicular to the direction of the wave

• Longitudinal - oscillations are parallel to the direction of the wave

What do displacement, amplitude + wavelength mean?

• Displacement - how far a particle has moved from the equilibrium

• Amplitude - the max displacement from the equilibrium

• Wavelength - the distance between two corresponding points on a wave

What do period, frequency + wave speed mean?

• Period - the time taken for one oscillation of a particle

• Frequency - the number of oscillations passing a given point per unit time

• Wave speed - the distance travelled by a wave per unit time

What does phase difference mean + equation?

• Phase difference - amount by which a wave lags behind another

• Δϕ = (x / λ) x 2π (phase difference = (separation in wavelengths of two particles / wavelength) x 2 pi)

What do in phase + in antiphase mean?

• In phase - phase difference of a multiple of 2π (e.g 0, 2π, 4π)

• Antiphase - phase difference of an odd multiple of π (e.g π, 3π, 5π)

What is the equation for frequency?

f = 1 / T (frequency = 1 / period)

How to find the frequency of wave using an oscilloscope?

1. Connect your signal to the oscilloscope

2. Adjust the volts/div (y-axis) so that the wave takes up most of the screen vertically

3. Adjust the timebase which is in seconds/div (x-axis) so that the wave takes up most of the screen horizontally

4. Count horizontal divisions for a whole cycle + multiply by timebase

5. Do f = 1 / T

What are the two equations for wave speed?

• v = d / t (velocity = distance / time)

• v = fλ (velocity = frequency x wavelength)

What does intensity mean + equation?

• Intensity - power transferred per unit area at right angles to the direction of travel of the wave

• I = P / A (intensity = power / area)

What is intensity proportional to?

Intensity ∝ amplitude²