Definitions Flashcards
Absolute Zero
The lowest possible temperature at which substances have the minimum internal energy
Acoustic Impedence
The product of the density of a substance and the speed of ultrasound in that substance
Attenuation
The decrease in the intensity of electromagnetic radiation as it passes through matter or space
Brownian motion
The continuous random motion of small particles suspended in a fluid, visible under a microscope
Delete
Two waves sources, or waves, that are coherent have a constant phase difference
Coupling gel
A gel with the acoustic impedance similar to that of skin, that is smeared onto the transducer and the patients skin before and ultrasound scan in order to fill air gaps and ensure that almost all the ultrasound enters the patients body
Decay constant
The probability of a decay of an individual nucleus per unit of time
Ideal gas
A model of a gas including assumptions similar to the behaviour of a real gas
Inelastic collision
A collision in which kinetic energy is transferred into other forms and is NOT conserved
Interference pattern
A pattern of constructive and destructive interference formed as waves overlap
Kirchoff’s First law
At any point in an electrical circuit, the sum of currents into that point is equal to the sum of the currents out of that point. Electrical charge is conserved
Kirchoff’s Second law
In a closed loop of an electrical circuit, the sum of the EMF’s is equal to the sum of the PD’s
Internal resistance
The resistance of a source of EMF due to its construction which causes a loss in energy/voltage as the charge passes through the source
Magnetic field lines
Lines of force drawn to represent a magnetic field pattern
Magnetic flux
The product of the component of the magnetic flux density perpendicular to a given area and that cross-sectional area. ø = BACosθ
Newtons first law of motion
A body will remain at rest of continue moving at a constant velocity unless acted upon by a resultant force
Newtons Second Law of Motion
The net force acting on an object is equal to the product of its mass and acceleration in the direction of the force.
Newtons Third Law
When two objects interact, each exerts and equal but opposite force and takes place in direction of the force
Newtons Laws of gravitation
The force between two point masses is directly proportional to the product of the masses and inversely proportional to the square of the separation between them
Binding energy
The minimum energy required to completely separate a nucleus into its constituent protons and neutrons
Gravitational Field
A field created around any object with mass, extending to infinity, but diminishing as distance from the centre of mass of the object increase
Gravitational field strength
The gravitational force exerted per unit of mass at a point within a gravitational field
Gravitational potential
The work done per unit of mass to bring an object from infinity to a point in the gravitational field
Gravitational potential energy
The capacity for doing work as a result of an objects position in a gravitational field
