physics CAIE Physics GCSE: Properties of Waves, Light, Sound and thermal

What is the electromagnetic spectrum?

The complete range of electromagnetic waves organized by their wavelengths and frequencies, encompassing waves from the lowest frequency radio waves to the highest frequency gamma rays, each possessing unique characteristics and uses in fields such as telecommunications, medicine, and scientific inquiry.

What are radio waves?

A category of electromagnetic waves characterized by long wavelengths, typically exceeding 1 millimeter, vital for communication technologies including AM and FM radio, television broadcasting, and wireless networks, allowing signals to be transmitted over vast distances.

What are microwaves?

Electromagnetic waves that lie between radio waves and infrared radiation within the spectrum, extensively applied in modern telecommunications including satellite communications, and in appliances like microwave ovens, where they heat food by inducing vibrations in water molecules.

What is infrared radiation?

Electromagnetic radiation situated between microwaves and visible light, particularly important in technologies such as thermal imaging, night-vision equipment, and heaters, as they transfer heat energy effectively.

What is visible light?

The segment of the electromagnetic spectrum that can be perceived by the human eye, with wavelengths ranging from approximately 400 to 700 nanometers, encompassing the array of colors essential for vision and playing a critical role in processes like photosynthesis.

What is ultraviolet light?

A category of electromagnetic radiation that features shorter wavelengths than visible light, harnessed in applications such as tanning, sterilization of surfaces, and in forensic science to initiate chemical reactions due to its high energy content.

What are X-rays?

High-energy electromagnetic radiation with very short wavelengths, primarily utilized in medical imaging to visualize internal structures of the body, such as bones and organs, and also employed in security screening processes.

What is gamma radiation?

Extremely high-energy electromagnetic waves generated during the radioactive decay of atoms, highly penetrating and applied in medical treatments, particularly in targeting and destroying cancer cells using radiation therapy.

What is a wave?

A phenomenon characterized by oscillations that propagate energy through a medium or space without resulting in permanent displacement of matter, manifesting in various forms, including sound waves, light waves, and water ripples.

What is a transverse wave?

A specific type of wave in which the oscillations occur perpendicular to the direction of wave propagation, with classic examples including light waves and ripples on a water surface.

What is a longitudinal wave?

Waves in which the oscillations occur parallel to the direction of energy transfer, with sound waves traveling through air being a primary example.

What is amplitude?

The maximum displacement of a wave from its rest position, reflecting the amount of energy carried by the wave.

What is wavelength?

The physical distance between consecutive points of a wave that are in phase, influencing both the frequency and energy of the wave.

What is frequency?

The number of complete cycles or waves that pass a specific point within a defined time frame, usually measured in hertz (Hz).

What is speed?

The velocity at which a wave moves through a medium, calculated using the relationship: speed = frequency x wavelength.

What is a wavefront?

A conceptual portrayal of a surface connecting points of a wave that share the same phase of oscillation.

What is reflection?

The phenomenon that occurs when a wave encounters a boundary or surface and bounces back into the original medium.

What is the angle of incidence?

The angle formed between an incoming wave and the line perpendicular to the surface at the point of incidence.

What is the angle of reflection?

The angle formed between the direction of the outgoing reflected wave and the normal line at the point of reflection.

What is refraction?

The bending of a wave as it transitions between different media due to a change in speed.

What is refractive index?

A dimensionless number that quantifies how much light slows down in a given medium compared to its speed in a vacuum.

What is Snell's Law?

A mathematical formula that depicts the relationship between the angles of incidence and refraction of a wave passing through two different media.

What is total internal reflection?

A phenomenon that occurs when a wave strikes a boundary at an angle larger than the critical angle, causing complete reflection within the original medium.

What is the critical angle?

The smallest angle of incidence at which total internal reflection takes place for a wave.

What is diffraction?

The bending and spreading of waves as they encounter obstacles or pass through narrow openings.

What are sound waves?

Longitudinal waves generated by vibrating objects, characterized by alternating regions of compression and rarefaction.

What is the speed of sound?

The speed at which sound waves propagate through a given medium, influenced by factors such as temperature, density, and the type of medium.

What is loudness?

The perceived intensity of sound, closely related to the amplitude of the sound wave.

What is pitch?

The perception of how high or low a sound is, determined by the frequency of the sound wave.

What is an echo?

The reflection of sound that returns to the listener after bouncing off a surface.

What are audible frequencies?

The range of frequencies that the human ear can detect, typically between 20 Hz and 20 kHz.

What are ultrasound waves?

Sound waves with frequencies higher than the human audible range, usually above 20 kHz.

What are compressions?

Regions in a longitudinal wave where particles are densely packed, resulting in an increase in pressure.

What are rarefactions?

Sections of a longitudinal wave where particles are spaced apart, leading to a decrease in pressure.

What is an optical fiber?

A thin, flexible strand of glass or plastic engineered to transmit light over long distances efficiently.

What is a converging lens?

A type of lens with a convex shape that converges incoming parallel light rays to a single focal point called the principal focus.

What is focal length?

The distance from the central point of a lens to its principal focus, signifying the lens's optical power.

What is a real image?

An image that results from light rays converging at a point and can be projected onto a physical surface.

What is a virtual image?

An image that appears to be produced from a location behind a lens or mirror, where light rays do not actually converge.

What is dispersion?

The phenomenon in which white light separates into its constituent colors or wavelengths when passing through a prism or similar optical apparatus.

What is monochromatic light?

Light that is composed of a single wavelength or frequency, displaying no variance in color.

What is a plane mirror?

A flat, reflective surface that adheres to the laws of reflection, producing virtual images.

What are solids?

A fundamental state of matter characterized by closely packed particles that establish a firm structure.

What are liquids?

A state of matter in which particles are closely packed but can move past each other.

What are gases?

A state of matter consisting of widely spaced particles with high kinetic energy, allowing them to expand and fill any available volume.

What is Brownian motion?

The random, erratic movement of microscopic particles suspended in a fluid, resulting from continuous collisions.

What is evaporation?

A gradual process wherein molecules at the liquid's surface gain sufficient kinetic energy to enter the gas phase.

What is boiling?

A vigorous transformation from liquid to gas characterized by the formation of bubbles throughout the liquid.

What is melting?

The phase transition in which a solid converts into a liquid upon reaching its melting point.

What is conduction?

The process of heat transfer through a material due to direct contact between particles.

What is convection?

The mechanism of heat transfer within fluids generated by the movement of bulk fluid currents.

What is radiation?

The process of emitting and transmitting energy in the form of electromagnetic waves or particles.

What is thermal energy?

The collective kinetic energy of particles in a substance, directly related to its temperature.

What is temperature?

A quantitative measure of the average kinetic energy of particles in a substance.

What is heat transfer?

The process of transferring thermal energy from one object or substance to another.

What is specific heat capacity?

The quantity of heat required to raise the temperature of one kilogram of a substance by one degree Celsius.

What is latent heat?

The energy absorbed or released by a substance during a phase change without a temperature change.

What is thermal conductivity?

A material property that describes its ability to conduct heat.

What is insulation?

Materials specifically designed to minimize heat transfer, employed to maintain temperature stability within various systems.

What is thermal equilibrium?

A state in which two or more objects in thermal contact achieve the same temperature.

What is the first law of thermodynamics?

A principle that asserts energy cannot be created or destroyed, only converted from one form to another.

What is the second law of thermodynamics?

A principle stating that the total entropy of an isolated system can only increase over time.

What is thermodynamics?

The field of physics that explores the relationships between heat and other forms of energy.

What is a heat engine?

A mechanism that converts thermal energy into mechanical work.

What is the purpose of refrigeration?

To extract heat from a given space to lower its temperature.

What does a heat exchanger do?

Facilitates the transfer of heat between two or more fluids without permitting them to mix.

What is specific latent heat?

The thermal energy required to change a unit mass of a substance from one phase to another while maintaining a constant temperature.

What is calorimetry?

The scientific technique for measuring heat changes in physical and chemical processes.

What is the conservation of energy?

The principle stating that energy in a closed system remains constant, able only to transform from one form to another.

What is entropy?

A measure of disorder or randomness in a system, frequently indicating the amount of energy within that system unavailable for doing work.

What are the three heat transfer mechanisms?

The processes of conduction, convection, and radiation, each exhibiting unique roles in the transfer of thermal energy.