Definitions Flashcards
Newton’s law of Gravitation. /2
Force is directly proportional to the square of POINT masses and inversely proportional to the square of separation of squares
State what is meant by specific latent heat? /2
It is the thermal energy per unit mass to change the state at constant mass
Define the radian. /2
radian is the angle subtended at the center of circle
when arc length is equal to radius
State by reference to simple harmonic motion, what is meant by angular frequency? /1
angular frequncy= 2pi x f
State what is meant by a field of force? /2
it is a region
where an object experiences a force
State what is meant by radioactive? /2
- nucleus emits particles
- emission from nucleus is random and spontaneous
State what is meant by decay constant? /2
probability of decay of a nucleus per unit time
Define gravitational field strength? /1
it is force per unit mass
state what is meant by the internal energy of a system? /2
internal energy is the RANDOM motion of kinetic energy and potential energy of all molecules
State what is meant by specific acoustic impedance? /2
product of speed of sound in medium and density of medium
Define capacitance. /1
charge/ potential difference
State Faraday’s law of electromagnetic radiation. /2
emf if proportional to the rate of change of magnetic flux linkage
State what is meant by the de Broglie wavelength? /2
wavelength associated with a particle has momentum
State what is meant by the Avogadro constant, NA? /1
number of atom in 12 g of Carbon- 12
State what is meant by the mole? /2
amount of substance
containing NA particles
Explain what is meant by the statement that the two bodies are in thermal equilibrium? /1
no net energy transfer between the bodies
Explain what is meant by gamma radiation (γ-radiation). /2
electromagnetic radiation
emitted from nucleus
Define specific heat capacity. /2
heat energy required per unit mass to raise the temperature by one degree of a substance
With reference to the photoelectric effect, state what is meant by the threshold frequency. /2
threshold frequency is the minimum frequency for electron to be emitted from the surface
Define gravitational potential of a point. /2
the gravitational potential at a point is the work done per unit mass in bringing the mass from infinity to a point in the gravitational field
State what is meant by electric field strength? /2
force per unit charge on a positive charge
state what is meant by electric field? /1
region where a charge experiences a force
State what is meant by electric potential at a point? /2
work done per unit charge
work done is moving positive charge from infinity
State Coulomb’s law? /2
force is proportional to the product of charges and inversely proportional to the square of separation
Define the tesla? /2
newton per ampere per metre
where current is perpendicular to magnetic field
define magnetic flux density? /2
magnetic flux density is the force per unit current per unit metre
current is perpendicular to magnetic field
State what is meant by a magnetic field? /1
region where there is a force exerted on a moving charge
define specific latent heat of fusion? /2
heat energy per unit mass
change of state at constant temperature between solid and liquid
State what is meant by internal energy of a system? /2
it is the random motion of molecules
internal energy = total potential + total kinetic energy
State what is meant by elastic collision? /1
no loss of kinetic energy
State what is meant by simple harmonic motion? /2
acceleration is proportional to displacement but in opposite direction
Define the radian? /2
angle subtended at the centre
where arc length= radius
what is meant by damping? /1
loss of energy
Explain what is meant by natural frequency of vibration of system? /1
frequency at which there is no resistive force acting on it
With reference to velocity and acceleration, describe uniform circular motion? /2
velocity has constant magnitude
acceleration is perpendicular to velocity
State what is meant by centripetal acceleration? /1
acceleration is perpendicular to velocity
State what is meant by a gravitational force? /1
force on a mass in a gravitational field
State by reference to the power dissipated in a resistor, what is meant by the root mean square (rms) value of an alternating voltage? /2
constant voltage that produces the same power as the alternating voltage
State what is meant by photoelectric effect? /2
emission of electrons from surface
when electromagnetic radiation is incident on electrons
State what is meant by work function? /1
minimum energy required for electron to leave surface
State what is meant by attenuation of an ultrasound wave? /1
loss of intensity of wave
State Hubble’s law? /2
speed is proportional to distance
where speed is speed of recession of galaxy from observer and distance is distance of galaxy away from observer
State Wien’s displacement law? /1
wavelength of maximum intensity is proportional to the temperature
State what is meant by red shift? /2
wavelength is greater than known value
due to movement of star away from observer
State what is meant by the luminosity of the star? /1
total power of the radiation emitted by the star
State what is meant by mass defect of a nucleus? /2
difference between mass of nucleus and mass of nucleons
where nucleons are separated to infinity
State what is meant by nuclear fusion?
two nuclei combine to form a single nucleus
fusion is initiated by very high temperature
State what is meant by nuclear fission?
a large nucleus divides to form smaller nuclei
State what is meant by spontaneous decay? /1
not affected by external factors
State what is meant by random decay? /1
cannot predict when a nucleus will decay
State what is meant by decay constant? /1
probability per unit time
State what is meant by radioactive decay? /2
emission of particles by unstable nucleus
spontaneous emission
Define magnetic flux linkage? /2
magnetic field strength x perpendicular cross sectional area x number of turns
State lenz’s law? /2
direction of induced emf is such as to oppose the change causing it
Define specific latent heat of vaporisation? /2
thermal energy per unit mass
energy required to change state between liquid and gas at constant temperature
State what is meant by resonance? /2
oscillations at maximum amplitude
when driving frequency equals natural frequency
Explain what is meant by a tracer. /1
a substance containing radioactive nuclei that is introduced into the body
Explain what is meant by annihilation. /1
a particle interacting with its antiparticle so that mass is converted into energy
State what is meant by luminosity of a star. /1
star with known luminosity
