Physics - Waves

OCR A-Level Physics 2022

Created: February 04, 2021 | Updated: August 25, 2024 | Read markdown | About these notes | View in context | Study these flashcards |

Flashcards

Wave symbols

What is the symbol for wavelength?

symbol-for-wavelength
\[\lambda\]

What is the symbol for the period of oscillation in a wave?

symbol-for-wave-period
\[T\]

What is the symbol for wave speed?

symbol-for-wave-speed
\[v\]

Defining wave quantities

What is the frequency of a wave?

frequency-definition

The number of wavelengths passing through a given point per unit time.

What is the period of oscillation of a wave?

period-of-oscillation-definition

The time taken for a wave to move one whole wavelength past a given point.

What is the wavelength?

wavelength-definition

The distance between any point on a wave and the next identical point on an adjacent wave.

What is the wave speed?

wave-speed-definition

The distance travelled by the wave per unit time.

Wave equations

What is the wave equation, in terms of $v$, $f$ and $\lambda$?

wave-equation-v-f-lambda
\[v = f\lambda\]

What is the formula for frequency in terms of period $T$?

frequency-from-period-formula
\[f = \frac{1}{T}\]

Types of wave

What is a progressive wave?

progressive-wave-definition

A wave that transfers energy but not matter.

What is a transverse wave?

transverse-wave-definition

A wave where the oscillations are perpendicular to the direction of energy transfer.

What is a longitudinal wave?

longitudinal-wave-definition

A wave where the oscillations are parallel to the direction of energy transfer.

What is a mechanical wave?

mechanical-wave-definition

A wave that requires a medium to travel through.

What is a wave that requires a medium to travel through called?

name-for-medium-requiring-wave

A mechanical wave.

What is special about electromagnetic waves?

electromagnetic-wave-no-medium

They don’t require a medium to travel through.

What is the name for waves that don’t require a medium to travel through?

name-for-mediumless-wave

An electromagnetic wave.

In a longitudinal wave, what’s one way you could measure the wave length?

measuring-longitudinal-wavelength

Find the distance between a pair of compressions/rarefactions.

What is the main difference between transverse and longitudinal waves?

transverse-vs-longitudinal-difference

In a transverse wave, oscillations are perpendicular to energy transfer whereas they are parallel in a longitudinal wave.

Since transverse and longitudinal waves are both progressive waves, what must be true?

both-progressive-transfer-energy

They both transfer energy but not matter.

Wave diagram features

What is this called?

identify-rarefaction

A rarefaction.

What is this called?

identify-compression

A compression.

What is missing?

identify-missing-equilibrium

The equilibrium position.

What is missing?

identify-missing-peak

The peak.

What is missing?

identify-missing-trough

The trough.

What is missing?

identify-missing-amplitude

Amplitude.

What is missing?

identify-missing-wavelength

Wavelength.

Wave profiles and graphs

What is a wave profile?

wave-profile-definition

A displacement-distance graph.

On a displacement-distance graph, what is on the $x$ axis?

displacement-distance-x-axis

Distance.

On a displacement-distance graph, what does the distance between two troughs equal?

trough-distance-equals-wavelength

The wavelength.

On a displacement-time graph, what does the time between two troughs equal?

trough-time-equals-period

The period.

Phase

What does this demonstrate?

phase-visual-demonstrates

The phase of a point on the wave.

What is phase difference measured in?

phase-difference-units
  • Degrees
  • Radians

How does the angle the radius makes with the circle relate to the wave?

radius-angle-is-phase

That’s the phase of the point on the wave.

What is the phase difference between $A$ and $E$?

phase-difference-a-to-e
\[360^{\circ}\]

What is the phase difference between $A$ and $C$?

phase-difference-a-to-c
\[180^{\circ}\]

What is the phase difference between $B$ and $D$?

phase-difference-b-to-d
\[180^{\circ}\]

What is the phase difference between $B$ and $C$?

phase-difference-b-to-c
\[90^{\circ}\]

What does it mean for two particles to be “in phase”?

in-phase-meaning

They are oscillating perfectly in step with each other.

What does it mean for two particles being “in antiphase”?

in-antiphase-meaning

They are oscillating perfectly out of step with each other.

What would the wave profile for $T - \frac{T}{2}$ look like?

wave-profile-after-half-period

What’s the formula for $\phi$, the phase difference in degrees between two points on a wave of wavelength $\lambda$ and separated by a distance $x$?

phase-difference-from-path-difference-degrees
\[\theta = \frac{x}{\lambda} \times 360^{\circ}\]

Colour and wavelength

What colour of visible light has the SHORTEST wavelength?

shortest-wavelength-colour

Blue.

What colour of visible light has the LONGEST wavelength?

longest-wavelength-colour

Red.

Superposition

What is the principle of superposition of waves?

principle-of-superposition

Displacement of a wave is equal to the sum of the displacements of the individual waves.

Phase difference formulae

What is the formula for the phase difference between two points with time difference $t$ and time period $T$?

phase-difference-from-time-difference
\[2\pi\left(\frac{t}{T}\right)\]

What is the formula for the phase difference between two points with distance between $d$ and wavelength $\lambda$?

phase-difference-from-distance
\[2\pi\left(\frac{d}{\lambda}\right)\]

Amplitude and distance from source

What is true about the amplitude of a wave $A$ and the distance from its source $r$?

amplitude-inverse-distance
\[A \propto \frac{1}{r}\]


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