IB Physics SL Terms

displacement

the change in position. i.e. final position and minus initial position. It is a vector

velocity

The rate of change of displacement

speed

The rate of change of distance

acceleration

the rate of change of velocity

linear momentum

mass × velocity

impulse

force × time or change in momentum

power

amount of energy transfer in 1 second. Average power equals the work done or the energy transferred, divided by the time taken to do the work

efficiency

useful work done divided by the total energy input

Newton's first law of motion

The property of matter called inertia means stationary objects tend to stay stationary and moving objects tend to keep moving. When the total force on an object is zero, the object will maintain whatever motion it had, when the total force became zero.

Newton's second law of motion

The rate of change of momentum of a body is equal to the net external force acting on the body

law of conservation of linear momentum

sum / total of momenta is constant for isolated system

Newton's third law of motion

For every force there is always another force equal in size and opposite in direction

principle of conservation of energy

When forces act and energy is transferred from one object to another and from one form to another, the total energy remains constant

The mole

the amount of a substance that contains as many elementary entities as the number of atoms in 12 g of the isotope carbon-12.

difference between evaporation and boiling with reference to temperature

evaporation takes place at any temperature/involves a reduction in temperature and boiling takes place at constant temperature

difference between evaporation and boiling with reference to surface area of a liquid

evaporation takes place at the surface of the liquid/depends on surface area of the liquid and boiling takes place throughout the liquid/is independent of surface area

temperature of an ideal gas

a measure of the molecules' average kinetic energy.

Internal energy

the total (potential energy and) kinetic energy of the molecules/ atoms/particles

Heating

the (non-mechanical) transfer of energy (from the surroundings/source) to the object

molar mass

The mass of one mole of a substance

Avogadro constant

in 1 mole of a substance, there are 6.02 x 10^23 particles of the substance

specific heat capacity

the amount of energy required to raise the temperature of unit mass through 1 K

thermal capacity

thermal energy required to change temperature by 1 K (1 deg C)

specific latent heat

The quantity of energy required to convert a unit mass of a substance from one state to another at constant temperature and pressure

pressure

The force per unit area of the particles colliding with the walls of the containing vessel

damping

Force that oppose the oscillations. It transfers energy away from the object in the form of heat and to the air molecules in the case of air resistance

natural frequency

the frequency of oscillation when released

resonance

a force applied to an oscillating object with a frequency equal to its natural frequency of oscillation

forced oscillations

an object is subjected to a force that causes it to oscillate at a different frequency than is natural

progressive (travelling) waves

wave that transfers energy

Snell's law

sin i/sin r = constant

principle of superposition

When two or more waves overlap, the displacement at any point is equal to the sum of the displacements of the individual waves at that point

displacement

distance in a particular direction; (accept in terms of energy transfer) (of a particle) from its mean position

amplitude

the greatest distance the medium moves from the mean

frequency

the number of oscillations it completes in 1 sec

period

The time to complete one oscillation

simple harmonic motion (SHM)

a = -w^2x

wavelength

the distance moved by a wavefront during one oscillation of the source or the distance between two successive crests of the wave

ray

direction in which energy is travelling

wave speed

distance travelled per unit time by the energy of the wave / by a wavefront

intensity

the energy is brings to a 1 m^2 area each second

The electromotive force (emf) of a cell

the power supplied by the cell per unit current from the cell.

Resistance

the ratio of potential difference across a device/load/resistor to current in the device/load/resistor

Ohm's law

the resistance of a conductor is constant provided its temperature is constant / the current is proportional to the voltage across

Internal resistance

The opposition to the movement of the ions and electrons within a cell

field of force

region/area/volume (of space) where a mass/charge experiences a force

Degraded energy

energy that is no longer available for the performance of useful work.

Stefan-Boltzmann law for a black body

energy emitted per unit time / power per unit area proportional to [absolute temperature/ temperature in K]^4

energy density

the energy that can be liberated per kg/stored per kg

Emissivity

ratio of power emitted by a body to the power emitted if it were a black body

Albedo

the fraction of energy/power incident in a surface that is reflected

a fuel

source of energy

enhanced greenhouse effect

increased (infra) radiation from the atmosphere to the Earth, increase in the greenhouse effect due to human activity;

surface heat capacity Cs

Surface heat capacity is the energy required to raise the temperature of 1 m^2 of the planet's surface by 1 K and is measured in J m^-2 K^-1

coefficient of volume expansion

the fractional change in the volume per degree change in temperature

fission

The process by which a heavy nucleus splits into two lighter nuclei

Critical mass

the amount of fissile material that will allow fission to be sustained

Isotope

nuclei with the same number of protons but different number of neutrons

Half-life

time it takes for the activity of a (radioactive) sample to halve

radioactive decay

a random and spontaneous process and that the rate of decay decreases exponentially with time

nucleon number A

Number of protons and neutrons in an atom

proton number Z

Number of protons in an atom

neutron number N

Number of neutrons in an atom

unified atomic mass unit

of the mass of one neutral atom of C

mass defect

difference in mass between mass of nucleus and mass of (totally) separate nucleons

binding energy

energy required to separate nucleus into separate nucleons

binding energy per nucleon

energy required to separate nucleus into separate nucleons per nucleon

de Broglie hypothesis

all particles have an associated wavelength which is given by hp, where h is Planck's constant and p is momentum

discrete energy spectrum

the energy is restricted to certain values

continuous energy spectrum

the energy can take on any value

decay constant

the probability of decay of a nucleus per unit time