1 X-ray Production Flashcards
The mass
–The mass of a body is a measure of its resistance to acceleration.
–Mass is measured in kilograms (kg).
Velocity
–Velocity is the speed of a body moving in a given direction.
–Velocity is measured in meters per second (m/s).
Acceleration
–Acceleration is the rate of change of velocity.
–Acceleration is measured in meters per second squared (m/s2).
Force
–A force causes a body to deviate from a state of rest or constant velocity (push or pull).
–Force = mass × acceleration, measured in newtons (N).
–The four physical forces in the universe are gravitational, electrostatic, strong, and weak.
The electrostatic force
–The electrostatic force causes protons and electrons to attract each other.
–Electrostatic forces hold atoms together.
Strong forces
–Strong forces hold the nucleus together.
Weak forces
–Weak forces are involved in beta decay.
Energy
–Energy is the ability to do work.
–Energy is measured in joules (J).
–Energy (joule) = power (watt) × time (second)
Einstein formula
–E = mc2 where E is energy, m is mass, and c is the velocity of light.
Electric charge
–Electric charge of an electron (or proton) is 1.6 × 10–19 coulomb (C).
Electric current
–Electric current, measured in amperes (A), is the flow of electrons through a circuit.
–An ampere is the amount of charge that flows divided by time.
–1 ampere = 1 coulomb per second
Power
–Power is the rate of performing work.
–Power is the energy used divided by time, measured in watts (W).
–1 watt = 1 joule per second
–Power (watt) = current (ampere) × voltage (volt)
A wave
–A wave is an entity that varies in space and time.
–Waves are characterized by a wavelength, frequency, and velocity.
Wavelength (λ)
–Wavelength (λ) is the distance between successive crests of waves.
–Wavelengths are measured in meters (m).
Frequency (f)
–Frequency (f) is the number of wave oscillations per unit of time.
–Frequencies are measured in cycles per second, where one cycle per second is equal
to one hertz (Hz).
The wave period
–The wave period is the time required for one wavelength to pass.
–Wave period is 1/f.
The wave velocity (v)
–The wave velocity (v) is the product of the wavelength and frequency, and measured in
meters per second (m/s).
–Velocity (m/s) = frequency (Hz) × wavelength (m)
Electromagnetic radiation
–Electromagnetic radiation is a wave that is associated with oscillating electric and magnetic fields.
–The product of the wavelength (λ) and frequency (f) of electromagnetic radiation is equal to the speed of light (c = fλ).
X-rays
–X-rays are a form of electromagnetic radiation.
–Low-frequency electromagnetic radiation has a long wavelength.
–High-frequency electromagnetic radiation has a short wavelength.
Photons
–Electromagnetic radiation is quantized, meaning that it exists in discrete quantities called photons.
–Photons may behave as waves or particles but have no mass.
–Photon energy is E = h f = h (c/λ), where h is Plank’s constant.
Generators consist of
–Generators consist of an input power supply, transformer, and rectification circuit.
Single-phase generators used in
–Dental radiography where teeth are relatively thin and longer exposure times are tolerable (no moving parts).
A transformer
–A transformer changes the size of the input voltage and is capable of producing high and low voltages.
–Np/Ns = Vp/Vs,
Rectification
–Rectification changes the AC voltage into a DC voltage across the x-ray tube.
–Rectification is achieved using diodes, which permit current to flow in only one direction.