Basic Physics and Electromagnetic Radiation

These flashcards cover key vocabulary and concepts in physics and electromagnetic radiation as discussed in the lecture.

Mass

A measure of a body's resistance to acceleration, measured in kilograms (kg).

Velocity

The speed of a body moving in a given direction, measured in meters per second (m/s).

Acceleration

The rate of change of velocity, measured in meters per second squared (m/s²).

Force

A push or pull that causes a body to change its state of rest or constant velocity; calculated as mass times acceleration (F = ma) and measured in newtons (N).

Gravitational force

One of four fundamental forces, it pulls objects toward the Earth and is important in cosmology.

Electrostatic force

The force that causes protons and electrons to attract each other, holding atoms together.

Strong force

The force that holds the nucleus of an atom together.

Weak force

The force involved in beta decay.

Energy

The ability to do work, measured in joules (J).

Kinetic energy (KE)

The energy of a body due to its motion, calculated as ½ mv².

Potential energy (PE)

The energy stored in an object due to its position, such as a raised ball.

Einstein's mass-energy equivalence

The principle that mass and energy are interchangeable, expressed as E=mc².

Rest mass energy

The energy equivalence of a particle at rest.

Electron volt (eV)

A unit of energy commonly used in diagnostic radiology, defined as the energy gained by an electron accelerated across a potential of 1 volt.

1 eV

Equal to 1.6 × 10⁻¹⁹ joules (J).

Voltage

An electric potential difference that drives the flow of electrons in a circuit, measured in volts (V).

Anode

The positive region in an electrical circuit where electrons are attracted.

Cathode

The negative region in an electrical circuit from which electrons are repelled.

Electric current

The flow of electrons, measured in amperes (A).

Ampere

The amount of charge that flows through a circuit in one second, defined as 1 coulomb per second.

Power

The rate of performing work, measured in watts (W), calculated as power = energy used/time.

1 watt

Equal to 1 joule per second.

Horsepower (HP)

A unit of power equivalent to 750 watts.

Wave

An entity that varies in space and time, characterized by wavelength, frequency, and velocity.

Wavelength (λ)

The distance between successive crests of a wave, measured in meters (m).

Frequency (f)

The number of wave oscillations per unit of time, measured in hertz (Hz).

Wave period

The time required for one wavelength to pass, calculated as 1 / frequency.

Wave velocity (v)

The speed at which a wave travels, calculated as v = f × λ.

Electromagnetic radiation

A wave associated with oscillating electric and magnetic fields, including visible light.

X-rays

A form of electromagnetic radiation produced by electron interactions.

Photon

A discrete quantity of electromagnetic radiation that exhibits both wave and particle characteristics.

Photon energy (E)

The energy carried by a photon, directly proportional to frequency and inversely proportional to wavelength.

Inverse Square Law

The principle stating that intensity decreases with the square of the distance from the source.

X-ray generator

A device that provides electrical power to the x-ray tube, converting only about 1% of the power to x-rays.

Transformer

A device that changes the size of voltage in electrical circuits, capable of producing high or low voltages.

Step-up transformer

A transformer that increases the voltage in a circuit.

Step-down transformer

A transformer that decreases the voltage in a circuit.

Full-wave rectification

A rectification method using diodes to convert AC voltage into DC voltage, resulting in two pulses per cycle.

Kvp (kilovolt peak)

The maximum voltage applied across the x-ray tube, important for x-ray production.

Ripple

The variation in voltage over time, which can affect x-ray production quality.

Three-phase power supply

A power supply system that uses three alternating voltages, providing more power than single-phase systems.

High-frequency inverter generators

Generators that transform AC input into high-frequency AC waveforms with nearly constant voltage.