9LC4: Energy and Waves Vocabulary Flashcards

Vocabulary practice flashcards covering energy resources, heat dissipation, wave properties, reflection, refraction, absorption, transmission, and the electromagnetic spectrum.

Thermal conductor

A material that will let heat flow through it.

Thermal insulator

A material that will not let heat flow through it.

Conduction

Heat transfer through a solid.

Dissipation

The process where energy is dissipated into a thermal store.

Transverse wave

A wave where energy is transferred perpendicular to the wave oscillations (e.g., light, surface water waves, all electromagnetic waves).

Longitudinal wave

A wave where energy is transferred parallel to the wave oscillations, creating compressions and rarefactions (e.g., sound waves, P waves).

Amplitude

Maximum displacement of a point on a wave from its undisturbed position (measured in metres).

Frequency

Number of waves passing a point per second (measured in Hertz, $\text{Hz}$).

Period

The time taken to complete one wave (measured in seconds).

Wave speed

The speed at which the energy is transferred through a medium (measured in metres/second). Calculated as wave speed = frequency $\times$ wavelength ($v = f \lambda$).

Wavelength

The distance from the point on one wave to the equivalent point on an adjacent wave (measured in metres).

Mechanical wave

A wave that needs a medium to travel through (e.g., sound waves, surface water waves).

Electromagnetic wave

A wave that does not need a medium to travel through (e.g., light, radio waves).

Normal

An imaginary line drawn at $90^\circ$ to the surface.

Law of Reflection

The principle stating that the angle of incidence ($i$) equals the angle of reflection ($r$), where angles are measured between the ray direction and the normal line at $90^\circ$ to the surface.

Refraction

The change in speed, wavelength, and direction of a wave caused by a change in the density of the material it enters.

Absorption

Occurs when energy is transferred from the wave into the particles of a substance.

Transmission

Occurs when a wave passes through a substance and emerges from the other side.

Coal

A non-renewable energy resource used for electricity generation, heating, and transport. Reliable output, but burning produces greenhouse gases ($\text{CO}_2$) and contributes to acid rain ($\text{SO}_2$).

Oil

A non-renewable energy resource used for transport and heating. Reliable compact energy source, but burning produces $\text{CO}_2$ and $\text{SO}_2$, and causes serious environmental damage if spilt.

Gas

A non-renewable energy resource used for electricity generation, heating, and transport. Reliable output; burning produces greenhouse gases ($\text{CO}_2$) but not $\text{SO}_2$.

Nuclear energy

A non-renewable energy resource used for electricity generation and military transport. Reliable output with no emissions other than radioactive waste; costly to build and decommission.

Biofuel

A renewable energy source used for transport and electricity generation; requires large areas of land for fuel crops, which can displace food crops in poorer nations.

Wind energy

A renewable energy source for electricity generation that only provides power when there is wind; turbines can be noisy, dangerous to birds, and ruin countryside appearance.

Hydro-electric energy

A renewable energy source for electricity generation requiring flooding of large land areas, which alters ecosystems and displaces residents.

Geothermal energy

A renewable energy source for electricity generation and heating, restricted to locations where hot rocks are near the surface (e.g., Iceland).

Tidal energy

A renewable energy source for electricity generation with variable output based on tides and high initial set-up costs; can alter habitats and hinder shipping.

Solar energy

A renewable energy source for electricity generation and heating dependent on light intensity; produces no power at night and has a high cost relative to power output.

Water waves energy

A renewable energy source for electricity generation whose output depends on waves, making it unreliable and capable of altering habitats.

Radio waves

Electromagnetic waves with long wavelength ($10^3\,\text{m}$) and low frequency ($10^5\,\text{Hz}$), produced by circuit oscillations and used for TV and radio communications with no known danger.

Microwaves

Electromagnetic waves ($\lambda = 10^{-2}\,\text{m}$, $f = 10^{10}\,\text{Hz}$) that transmit through the atmosphere; used for satellite communication and cooking food; danger is internal heating.

Infrared radiation

Electromagnetic waves ($\lambda = 10^{-5}\,\text{m}$, $f = 10^{13}\,\text{Hz}$) emitted/absorbed well by dark matt surfaces; used for electrical heaters, cooking, and infrared cameras; danger is skin burns.

Visible light

Electromagnetic waves ($\lambda = 10^{-6}\,\text{m}$, $f = 10^{14}\,\text{Hz}$) in the frequency range detectable by the human eye; used in fibre optic communications.

Ultraviolet (UV)

Ionising electromagnetic radiation ($\lambda = 10^{-8}\,\text{m}$, $f = 10^{16}\,\text{Hz}$) used in energy-efficient lamps and sun tanning; can damage cells and cause skin cancer.

X-Rays

Ionising electromagnetic radiation ($\lambda = 10^{-10}\,\text{m}$, $f = 10^{18}\,\text{Hz}$) absorbed by bones but transmitted through soft tissue; used for medical imaging and treatments; causes cell damage, mutations, and cancer.

Gamma Rays

Short wavelength ($10^{-12}\,\text{m}$), high frequency ($10^{20}\,\text{Hz}$) ionising electromagnetic radiation created by nuclear changes; used in medical imaging and treatments; causes cell damage, mutations, and cancer.