the key words paper 1 Flashcards
Power
Power is defined as the rate at which energy is transferred or at which work is done
Current
Electric current is the rate of flow of electric charge
Ohmic
conductor
The current through an ohmic conductor at constant temperature is
directly proportional to the potential difference across it
National Grid
The National Grid is a system of cables and transformers linking power
stations to consumers
Internal energy
Internal energy is the total kinetic and potential energy of all the particles that make up a system
Specific heat capacity
The specific heat capacity of a substance is the amount of energy required to raise the temperature of one kilogram of the substance by one degree Celsius
Specific latent heat
The specific latent heat of a substance is the amount of energy required to change the state of one kilogram of the substance with no change in temperature
Activity
Activity is the rate at which a source of unstable nuclei decays
Count-rate
Count-rate is the number of decays recorded each second by a detector
Half-life
The half-life of a radioactive isotope is the time it takes for the number of nuclei of the isotope in a sample to halve
or
The time it takes for the count-rate, or activity, from a sample containing the radioactive isotope to fall to half its initial level
Contamination
Contamination is the unwanted presence of material containing radioactive atoms on other material
Irradiation
Irradiation is the process of exposing an object to nuclear radiation
Fission
Nuclear fission is the splitting of a large and unstable nucleus
Fusion
Nuclear fusion is the joining of two light nuclei to form a heavier nucleus
Joule
One joule of work is done when a force of one newton causes a displacement of one metre
Moment
The turning effect of a force is called the moment of a force and is equal to the force multiplied by the perpendicular distance from the pivot to the line of action of the force
Displacement
Displacement includes both the distance an object moves and the direction it moves from its start point
Velocity
The velocity of an object is its speed in a given direction
Newton’s
First Law
If the resultant force acting on an object is zero and the object is:
▪ stationary, the object remains stationary
▪ moving, the object continues to move at the same velocity
Newton’s
Second Law
The acceleration of an object is proportional to the resultant force acting on the object and inversely proportional to the mass of the object
Newton’s
Third Law
Whenever two objects interact, the forces they exert on each other are
equal and opposite
Stopping
distance
The stopping distance of a vehicle is the sum of the distances the vehicle
travels during the driver’s reaction time (thinking distance) and the
distance it travels under the braking force (braking distance)
Momentum
Momentum is defined as mass times velocity
Conservation
of momentum
In a closed system, the total momentum before an event is equal to the
total momentum after the event
Amplitude
The amplitude of a wave is defined as the maximum displacement of a point on a wave away from its undisturbed position
Wavelength
The wavelength of a wave is the distance from a point on one wave to the equivalent position on the adjacent wave
Frequency
The frequency of a wave is the number of waves passing a point each second
