IB Physics Topic 3 Definitions

This page contains our IB Physics definitions for topic 3. By learning each one of these definitions, you will fully cover the content for IB Physics 'Wave Behaviour'.
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amplitude

It is the maximum displacement of the particle from its mean position

Analyzer

It is a polarizer that detects the angle of polarization

Angular frequency

It is the angle oscillated per unit time

Antinode

It is a point a maximum amplitude in a standing wave

Blue shift

It is the increase in frequency of light due to the moving closer of an observer or source

Boundary conditions

These are the conditions that must be present at the edges of a system for a standing wave to be formed. Also called resonant modes

Complete constructive interference

It is the interference of in phase waves leading to a summation into a larger amplitude wave

Complete destructive interference

It is the interference of out of phase waves leading to a summation into a zero amplitude wave

compression

It is an area of high particle density in a longitudinal wave

Constructive interference

It is interference that increases the displacement of both waves

Critical angle

It is the angle at which there is no refraction and complete reflection back into the medium

Destructive interference

It is interference that decreases the displacement of both waves

Diffraction

It is the spreading of waves after passing through apertures, resulting in an energy distribution in the geometric shadow region

Diffuse reflection

It is the reflection of several rays from a rough surface

displacement

It is the net distance an object has travelled from its starting point in a direction

electromagnetic wave

It is a transverse wave with an electrical and magnetic component

First harmonic

It is the resonant mode with the lowest frequency

frequency

It is the number of oscillations in one second

Fringes

It is the pattern of light and dark regions formed by diffraction

Geometric shadow region

It is the region not in line with the aperture

In phase waves

These are waves with a phase difference of zero or path difference of nλ

Intensity

It is the energy per unit area

Interference

It is the superposition of two waves of the same type when they come together

longitudinal wave

It is a travelling wave where the oscillation is parallel to the direction of energy transfer

Monochromatic source

It is a source that emits one frequency of light

Node

It is a point at rest in a standing wave

oscillations

They are the continual movement of an object around a fixed point, creating a cyclical path the object travels to constantly interchange between kinetic and potential energy

Out of phase waves

These are waves with a phase difference of 180° or path difference of (n+1/2)λ

Perfect reflection

It is the reflection of a single ray from a smooth surface

period

It is the time it takes to complete one oscillation

phase difference

It is the measure of the alignment of two oscillations

Plane of vibration

It is the plane of the electric field of an electromagnetic wave and the direction of wave propagation

Plane-polarized light

It is light with a fixed plane of vibration

Polarizer

It is a device that transforms unpolarized light into plane-polarized light

rarefaction

It is an area of low particle density in a longitudinal wave

ray

It represents the direction of travel of wave energy

Red shift

It is the decrease in frequency of light due to the moving away of an observer or source

Reflection

It is the scattering of a wave when it hits a surface

Refraction

It is the change in direction of a wave when it crosses from one medium to another due to a change in wave speed

Simple harmonic motion

It is the motion of an object where its acceleration is proportional to and towards its displacement

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Single-slit diffraction

It is the spreading of a wave through a single aperture

Standing wave

It is a wave whose spatial pattern remains constant whilst the amplitude changes

Total internal reflection

It is the complete reflection of a wave back into the medium

transverse wave

It is a travelling wave where the oscillation is perpendicular to the direction of energy transfer

travelling wave

It is an oscillating wave that transfers energy through a medium via the movement of particles in the direction of the wave at a constant speed

Unpolarized light

It is light with a randomly varying plane of vibration

Wave pulse

It is a non-sinusoidal disturbance of a medium that propagates as a half of a wave

Wavefront

It represents the moving together of oscillation points

wavelength

It is the distance one oscillation travels

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