Deffinitions Flashcards
Longitudinal wave
The particles vibrate along the same direction of the wave
Transverse wave
The particles move at right angles to the direction of travel of the wave
Frequency i
The number of waves per second
Period
The time taken for one wave to pass a point
Diffraction
The bending of waves through gaps or around obstacles
Refraction
The change in speed of light as it passes from one medium to another
Alpha particle
A particle made up of 2 protons and 2 neutrons
It is the nucleus of a helium atom
Beta particle
A fast moving electron
Gamma ray
Am electromagnet wave of very high frequency and energy
Ionisation
The addition or removal of an electron from a neutral atom
Activity
The number of nuclear decays per second
Absorbed dose
The energy absorbed by a material per unit mass
Equivalent dose
The absorbed dose multiplied by the radiation weighing factor
Equivalent dose rate
The equivalent dose per unit time
Half-life
The time taken for the activity of a radioactive source to decrease to half of it’s original value
Nuclear fission
The process in which an unstable, heavy atomic nucleus splits into two or more lighter nuclei with energy being released
Chain reaction
When neutrons released in nuclear fission reactions go on to hit other nuclei, causing further fission reactions, and the cycle repeats
Nuclear fusion
The process of small nuclei joining together to form a larger nucleus, with energy being released
Plasma containment
The use of powerful magnetic fields to prevent hydrogen plasma from physically touching any parts of a nuclear reactor
Heat
A measure of the total kinetic energy of the particles in an object
Temperature
A measure of the average kinetic energy of the particles in an object
Specific heat capacity
The amount of heat energy required to raise the temperature of 1kg of a substance by degrease Celsius
Specific latent heat
The amount of heat energy required to change the state of 1kg of a substance
Specific latent heat of fusion
The energy required to change 1kg if a solid into a liquid at it’s melting point
Specific latent heat of vaporisation
The energy required to change 1kg of a liquid into a gas at its boiling point
Pressure
The force per unit area
Absolute zero
The temperature it which the pressure in a substance is zero
This occurs at -273C or 0k
Where we assume the kinetic energy of the particles is zero
Boyle’s law
For a fixed mass of gas at constant temperature, pressure is inversely proportional to volume
Gay-Lussac’s law
For a fixed mass of gas at constant volume, pressure is directed proportional to temperature (in K)
Charles’ law
For a fixed mass of gas at constant pressure, volume is directly proportional to temperature ( in k)
Scalar
A quantity that consists of a magnitude (size) only
Vector
A quantity that consists of a magnitude and direction
Speed
The distance traveled per unit time
Average speed
The total distance traveled by an object measured over the total time taken
Instantaneous speed
The speed of an object at a particular moment in time
Instantaneous speed
The speed of an object at a particular moment in time
Velocity
The displacement per unit time
Acceleration
The change in velocity per unit time taken
Acceleration
The change in velocity per unit time
Gravitational field strength
The gravitational force per unit mass
Newton’s first law
An object will remain at rest or move at a constant speed in a straight line unless acted upon by an unbalanced force
Newton’s second law
F=ma
Free fall
The movement of any object under the influence of gravity alone
Terminal velocity
For an object in free fall, a constant speed is reached when the upward force on the object is balanced by the downward force on the object
Newton’s third law
Every action has an equal but opposite reaction
Projectile motion
The curved path taken by a projectile due to its constant horizontal velocity and constant vertical acceleration
Satellite
A special type of projectile that follows a circular orbit due to its constant horizontal velocity and constant vertical acceleration
Work done
A form of energy which describes the force applied to move an object a certain distance
Electrical current
The electrical charge transferred per second
Direct Current (D.C.)
The flow of current in one direction only
Alternating current (A.C.)
The back and forth flow of current
Current changes every fraction of a second
Potential difference (voltage)
The energy supplied to each coulomb of charge that passes through a power supply
Resistance
The opposition to current flow
Ohm’s law
For a fixed temperature, the voltage is directly proportional to the current passing through it
Transistor
A semiconductor device that can be used as an electronic switch
Electrical power
The electrical energy transferred per second
Fuse
A safety device containing a thin wire which will break (melt) when too large a current flows through it
