Definitions

Question 1

Hooke’s Law

Answer 1

The extension of a spring, x, is directly proportional to force applied, F, provided the limit of proportionality is not reached/exceeded.

Question 2

Stress

Answer 2

The force applied per unit area of cross section.

Question 3

Ultimate Tensile Stress

Answer 3

The maximum stretching force per unit area without the material breaking.

Question 4

Strain

Answer 4

The ratio of the change in the length of a specimen to its original length.

Question 5

Young’s Modulus

Answer 5

A measure of the stiffness of a material, determined by the ratio of stress divided by strain.

Question 6

Microscopic

Answer 6

Small scale

Question 7

Macroscopic

Answer 7

Large scale

Question 8

Isothermal

Answer 8

Constant temperature

Question 9

Boyles Law

Answer 9

For a fixed mass of gas at constant temperature the volume is inversely proportional to the pressure.

Question 10

Charles Law

Answer 10

For a fixed mass of gas at constant pressure, the volume is directly proportional to the temperature in kelvin.

Question 11

Pressure Law

Answer 11

For a fixed mass of gas at constant volume, the pressure is directly proportional to the temperature in kelvin.

Question 12

Mole

Answer 12

The mole is the amount of substance which contains as many particles as there are in 0.012kg of carbon 12.

Question 13

Specific Heat Capacity

Answer 13

The thermal energy required to raise the temperature of a body of mass 1kg by 1K.

Question 14

STP

Answer 14

Standard Temperature and Pressure, taken as 0 degrees Celsius and 1x10^5 Pa.

Question 15

Define Newton’s first law

Answer 15

Every body will continue in a state of rest or uniform velocity unless acted on by a resultant force

Question 16

Define Newton’s second law

Answer 16

Acceleration is directly proportional to 𝐹_𝑅 acting in the same direction and is inversely proportional to mass, 𝐹_𝑅 = ma

Question 17

Define Newton’s third law

Answer 17

If body A exerts a force on body B, body B exerts an equal and opposite force on body A

Question 18

Centripetal

Answer 18

Centre seeking

Question 19

Angular velocity

Answer 19

The rate of change of angular displacement, w = Ø/t

Question 20

Simple harmonic motion

Answer 20

The acceleration is directly proportional to the displacement and is always directed towards the fixed position, a = -w^2 x

Question 21

Damping

Answer 21

Resistive force which opposes motion and so causes the amplitude to decrease

Question 22

Resonance

Answer 22

A vibrating system or external force drives another to oscillate with greater amplitude at specific frequencies

Question 23

Free vibrations

Answer 23

No energy is transferred to or from the system, thus amplitude remains fixed

Question 24

Forced vibrations

Answer 24

Forced to oscillate at the frequency of an external oscillator (giving it energy)

Question 25

Isotope

Answer 25

Atoms of an element with the normal (same) number of protons and electrons, but different numbers of neutrons

Question 26

Ionisation

Answer 26

Convert (an atom, molecule, or substance) into an ion or ions, typically by removing one or more electrons

Question 27

Background radiation

Answer 27

Ionising radiation present in the environment

Question 28

Exponential decay

Answer 28

Decay in which the amount falls by a fixed fraction per unit time

Question 29

Activity

Answer 29

The number of disintegrations per second in a sample, measured in Bq

Question 30

Decay constant

Answer 30

The decay constant is the fraction of the total number of nuclei present to decay per unit time / second

Question 31

Half life

Answer 31

The time for the number of radioactive nuclei present to decay to half its original value

Question 32

Unified atomic mass

Answer 32

Unified atomic mass is 1/12 of the mass of one atom of Carbon 12, u = 1.66 x10^-27

Question 33

Electron volt (eV)

Answer 33

A unit of energy equal to the work done on an electron in accelerating it through a potential difference of 1 volt, 1 eV = 1.6 x10^-19

Question 34

Radian

Answer 34

In radian measure, the angle, in radians, is expressed as the ratio of the arc length to the radius.