Definitions

Question 1

Define precision

Answer 1

A measure of how close the results of an experiment agree with each other

Question 2

Define accuracy

Answer 2

A measure of how close the results of an experiment agree with the true value

Question 3

Define a random error

Answer 3

Errors of measurements in which the measured quantities differ from the mean value with different magnitudes and directions

Question 4

Define a systematic error

Answer 4

Errors of measurements in which the measured quantities are displaced from the true value by fixed magnitude and in the same direction

Question 5

Define homogeneous

Answer 5

units on both sides of the equation are identical

Question 6

Define velocity

Answer 6

The rate of change of displacement

Question 7

Define acceleration

Answer 7

The rate of change of velocity

Question 8

Define the resultant force

Answer 8

A single force upon an object found by adding all the forces acting upon an object

Question 9

Define the normal contact force

Answer 9

A force perpendicular to the surface experienced by a body when it is in physical contact with something else

Question 10

Define moment

Answer 10

The product of the force and the perpendicular distance between the axis of rotation and the line of action of the force

Question 11

Define the centre of gravity of an object

Answer 11

The point on an object through which the entire weight of the object may be considered to act

Question 12

Define work done

Answer 12

The product of the force and the displacement of the object in the direction of that force

Question 13

Define gravitational potential energy

Answer 13

the amount of work done in order to raise the body to a height

Question 14

Define power

Answer 14

The rate of energy transfer

Question 15

Define stress

Answer 15

The tensile force applied per unit of crossectional area

Question 16

Define strain

Answer 16

The ratio of change in length and original length of a material

Question 17

Define young modulus

Answer 17

The ratio of stress and strain

Question 18

Define the elementary charge

Answer 18

The charge of an electron

Question 19

Define current

Answer 19

The rate of flow of charge

Question 20

Define potential difference

Answer 20

The electrical energy converted into other forms of energy per unit charge

Question 21

Define the electron volt

Answer 21

The energy gained by an electron across a p.d. of one volt

Question 22

Define the electromotive force

Answer 22

The energy converted from other forms to electrical per unit charge

Question 23

Define frequency

Answer 23

The number of waves passing a point per unit time

Question 24

Define displacement

Answer 24

The distance of the oscillating particle from its equilibrium position

Question 25

Define amplitude

Answer 25

The magnitude of the maximum displacement of the oscillating particle from the equilibrium position

Question 26

Define phase difference

Answer 26

The difference in rotation in the wave cycle between two points on a wave

Question 27

Define intensity

Answer 27

The rate of transfer of energy per unit area perpendicular to the direction of travel of the wave

Question 28

Define work function

Answer 28

The minimum amount of energy necessary to remove a free electron from the surface of the material

Question 29

Define a photon

Answer 29

A discrete packet of electromagnetic energy

Question 30

Define internal energy

Answer 30

The sum of the individual random kinetic and potential energies of particles in a substance

Question 31

Define specific heat capacity

Answer 31

The change in thermal energy per unit mass to change the temperature of the material by 1 K

Question 32

Define specific latent heat

Answer 32

The energy required per unit mass to change the state of a substance without any temperature change

Question 33

Define angular displacement

Answer 33

The angle subtended at the centre of a circle by an arc of equal length to the radius

Question 34

Define angular velocity

Answer 34

The rate of change of angular displacement

Question 35

Define resonance

Answer 35

When an oscillating system is driven at a frequency which is the same as its natural frequency

Question 36

Define gravitational field strength

Answer 36

The gravitational force per unit mass acting on a mass placed at that point

Question 37

Define gravitational potential energy

Answer 37

The work done by an external force in bringing that point mass from infinity to that point

Question 38

Define gravitational potential

Answer 38

The work done per unit mass, by an external force, in bringing the mass from infinity to that point

Question 39

Define capacitance

Answer 39

The charge stored per unit potential difference across the capacitor

Question 40

Define time constant

Answer 40

The time for a capacitor to discharge to 37% of the original charge stored

Question 41

Define electric field strength

Answer 41

The electrostatic force per unit charge experienced by a positive test charge placed at that point

Question 42

Define electric potential

Answer 42

The work done per unit charge in bringing a positive test charge from infinity to that particular point without acceleration

Question 43

Define electrical potential energy

Answer 43

The work done by an external force in bringing the charge from infinity to a point

Question 44

Define magentic flux

Answer 44

The product of the magnetic flux density normal to the surface and the area of the surface

Question 45

Define magnetic flux linkage

Answer 45

The product of the number of turns of the coil and the magnetic flux linking each turn

Question 46

Define activity

Answer 46

The average number of unstable nuclei disintegrating per unit time

Question 47

Define the decay constant

Answer 47

Probability of decay per unit time

Question 48

Define the mass defect

Answer 48

The difference between the mass of the separated nucleons and the combined mass of the nucleus

Question 49

Define attenuation

Answer 49

The reduction in wave intensity as it propagates through a material

Question 50

Define acoustic impedance

Answer 50

The product of the density of a substance and the speed of the wave through it