Definitions

Question 1

Newton’s law of Gravitation. /2

Answer 1

Force is directly proportional to the square of POINT masses and inversely proportional to the square of separation of squares

Question 2

State what is meant by specific latent heat? /2

Answer 2

It is the thermal energy per unit mass to change the state at constant mass

Question 3

Define the radian. /2

Answer 3

radian is the angle subtended at the center of circle
when arc length is equal to radius

Question 4

State by reference to simple harmonic motion, what is meant by angular frequency? /1

Answer 4

angular frequncy= 2pi x f

Question 5

State what is meant by a field of force? /2

Answer 5

it is a region
where an object experiences a force

Question 6

State what is meant by radioactive? /2

Answer 6

• nucleus emits particles
• emission from nucleus is random and spontaneous

Question 7

State what is meant by decay constant? /2

Answer 7

probability of decay of a nucleus per unit time

Question 8

Define gravitational field strength? /1

Answer 8

it is force per unit mass

Question 9

state what is meant by the internal energy of a system? /2

Answer 9

internal energy is the RANDOM motion of kinetic energy and potential energy of all molecules

Question 10

State what is meant by specific acoustic impedance? /2

Answer 10

product of speed of sound in medium and density of medium

Question 11

Define capacitance. /1

Answer 11

charge/ potential difference

Question 12

State Faraday’s law of electromagnetic radiation. /2

Answer 12

emf if proportional to the rate of change of magnetic flux linkage

Question 13

State what is meant by the de Broglie wavelength? /2

Answer 13

wavelength associated with a particle has momentum

Question 14

State what is meant by the Avogadro constant, NA? /1

Answer 14

number of atom in 12 g of Carbon- 12

Question 15

State what is meant by the mole? /2

Answer 15

amount of substance
containing NA particles

Question 16

Explain what is meant by the statement that the two bodies are in thermal equilibrium? /1

Answer 16

no net energy transfer between the bodies

Question 17

Explain what is meant by gamma radiation (γ-radiation). /2

Answer 17

electromagnetic radiation
emitted from nucleus

Question 18

Define specific heat capacity. /2

Answer 18

heat energy required per unit mass to raise the temperature by one degree of a substance

Question 19

With reference to the photoelectric effect, state what is meant by the threshold frequency. /2

Answer 19

threshold frequency is the minimum frequency for electron to be emitted from the surface

Question 20

Define gravitational potential of a point. /2

Answer 20

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

Question 21

State what is meant by electric field strength? /2

Answer 21

force per unit charge on a positive charge

Question 22

state what is meant by electric field? /1

Answer 22

region where a charge experiences a force

Question 23

State what is meant by electric potential at a point? /2

Answer 23

work done per unit charge
work done is moving positive charge from infinity

Question 24

State Coulomb’s law? /2

Answer 24

force is proportional to the product of charges and inversely proportional to the square of separation

Question 25

Define the tesla? /2

Answer 25

newton per ampere per metre where current is perpendicular to magnetic field

Question 26

define magnetic flux density? /2

Answer 26

magnetic flux density is the force per unit current per unit metre current is perpendicular to magnetic field

Question 27

State what is meant by a magnetic field? /1

Answer 27

region where there is a force exerted on a moving charge

Question 28

define specific latent heat of fusion? /2

Answer 28

heat energy per unit mass change of state at constant temperature between solid and liquid

Question 29

State what is meant by internal energy of a system? /2

Answer 29

it is the random motion of molecules internal energy = total potential + total kinetic energy

Question 30

State what is meant by elastic collision? /1

Answer 30

no loss of kinetic energy

Question 31

State what is meant by simple harmonic motion? /2

Answer 31

acceleration is proportional to displacement but in opposite direction

Question 32

Define the radian? /2

Answer 32

angle subtended at the centre where arc length= radius

Question 33

what is meant by damping? /1

Answer 33

loss of energy

Question 34

Explain what is meant by natural frequency of vibration of system? /1

Answer 34

frequency at which there is no resistive force acting on it

Question 35

With reference to velocity and acceleration, describe uniform circular motion? /2

Answer 35

velocity has constant magnitude acceleration is perpendicular to velocity

Question 36

State what is meant by centripetal acceleration? /1

Answer 36

acceleration is perpendicular to velocity

Question 37

State what is meant by a gravitational force? /1

Answer 37

force on a mass in a gravitational field

Question 38

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

Answer 38

constant voltage that produces the same power as the alternating voltage

Question 39

State what is meant by photoelectric effect? /2

Answer 39

emission of electrons from surface when electromagnetic radiation is incident on electrons

Question 40

State what is meant by work function? /1

Answer 40

minimum energy required for electron to leave surface

Question 41

State what is meant by attenuation of an ultrasound wave? /1

Answer 41

loss of intensity of wave

Question 42

State Hubble's law? /2

Answer 42

speed is proportional to distance where speed is speed of recession of galaxy from observer and distance is distance of galaxy away from observer

Question 43

State Wien's displacement law? /1

Answer 43

wavelength of maximum intensity is proportional to the temperature

Question 44

State what is meant by red shift? /2

Answer 44

wavelength is greater than known value due to movement of star away from observer

Question 45

State what is meant by the luminosity of the star? /1

Answer 45

total power of the radiation emitted by the star

Question 46

State what is meant by mass defect of a nucleus? /2

Answer 46

difference between mass of nucleus and mass of nucleons where nucleons are separated to infinity

Question 47

State what is meant by nuclear fusion?

Answer 47

two nuclei combine to form a single nucleus fusion is initiated by very high temperature

Question 48

State what is meant by nuclear fission?

Answer 48

a large nucleus divides to form smaller nuclei

Question 49

State what is meant by spontaneous decay? /1

Answer 49

not affected by external factors

Question 50

State what is meant by random decay? /1

Answer 50

cannot predict when a nucleus will decay

Question 51

State what is meant by decay constant? /1

Answer 51

probability per unit time

Question 52

State what is meant by radioactive decay? /2

Answer 52

emission of particles by unstable nucleus spontaneous emission

Question 53

Define magnetic flux linkage? /2

Answer 53

magnetic field strength x perpendicular cross sectional area x number of turns

Question 54

State lenz's law? /2

Answer 54

direction of induced emf is such as to oppose the change causing it

Question 55

Define specific latent heat of vaporisation? /2

Answer 55

thermal energy per unit mass energy required to change state between liquid and gas at constant temperature

Question 56

State what is meant by resonance? /2

Answer 56

oscillations at maximum amplitude when driving frequency equals natural frequency

Question 57

Explain what is meant by a tracer. /1

Answer 57

a substance containing radioactive nuclei that is introduced into the body

Question 58

Explain what is meant by annihilation. /1

Answer 58

a particle interacting with its antiparticle so that mass is converted into energy

Question 59

State what is meant by luminosity of a star. /1

Answer 59

star with known luminosity