Definitions Flashcards
(104 cards)
1
Q
What are derived units?
A
Units that are combinations of base units.
Derived units may be multiplied or divided but not added or subtracted.
2
Q
Define homogeneous in the context of units.
A
Base units on the left side are the same as those on the right side
3
Q
What is a scalar quantity?
A
A quantity that has magnitude/size.
4
Q
What is a vector quantity?
A
A quantity that has magnitude/size and direction.
5
Q
Define accuracy in measurements.
A
the degree of agreement between the
result of a measurement and the true value of
quantity.
6
Q
Define precision in measurements.
A
the degree of agreement of repeated
measurements of the same quantity (regardless of
whether it is close to the true value or not)
7
Q
What are random errors?
A
- Random fluctuations or scatter about a true value
- Caused by the observers and environmental
techniques - This can be reduced by repeating and averaging
- When random error is small, measurement is precise
8
Q
What is uncertainty in measurements?
A
The range of value within which a measurement is likely to be.
9
Q
Define acceleration.
A
Rate of change of velocity.
10
Q
What is displacement?
A
distance in a certain direction
11
Q
Differentiate between distance and displacement.
A
Distance: total length moved irrespective of direction.
Displacement: distance in a certain direction
12
Q
What is free fall?
A
The downward motion of an object under the influence of only the gravity force with constant acceleration (g = 9.81 m/s²).
13
Q
What is momentum?
A
The product of an object’s mass and velocity.
14
Q
Define force.
A
Rate of change of momentum
15
Q
What is impulse?
A
change of momentum
16
Q
What type of collisions conserve total momentum?
A
Both Elastic collisions and inelastic collisions
17
Q
What does the principle of conservation of momentum state?
A
Total momentum of an isolated system remains constant if no external forces act on it.
18
Q
What is terminal velocity?
A
Constant speed of an object when the resultant force is zero due to large air resistance.
19
Q
Define weight.
A
The force due to the gravitational field acting on an object. It is the product of mass and gravity acceleration
20
Q
What is the center of gravity?
A
point through which the entire weight
of the object may be considered to act
21
Q
State Newton’s 1st Law.
A
A body remains at rest or constant velocity unless acted upon by a resultant external force or torque
22
Q
State Newton’s 2nd Law.
A
the rate of change of momentum is proportional to The resultant force and occurs in the direction of force
23
Q
State Newton’s 3rd Law.
A
For every force, there is another force equal in magnitude and opposite direction.
24
Q
What is density?
A
mass per unit volume of a substance.
25
What does equilibrium mean in physics?
Sum of forces in all directions is zero,
Sum of clockwise and anticlockwise torque is zero
26
What is pressure?
The perpendicular/normal force applied per unit area.
27
What is moment about a point?
Product of the force and the perpendicular distance between the line of action and pivot.
28
Define a couple in terms of torque.
Two equal in magnitude and parallel but opposite direction forces whose line of action is different, producing rotation only.
29
What is upthrust?
The resultant force on a submerged object due to pressure difference in a fluid.
30
Fill in the blank: The average/peak is not the true value; the readings are not centered around the true value, indicating _______.
Systematic Error.
31
Fill in the blank: The _______ of momentum of an isolated system remains constant if no external forces act.
Sum
32
True or False: Total kinetic energy of a system of collision is always conserved.
False.
33
Torque vs moment
Torque: distance between 2 forces
Momen: distance between force and pivot point
34
What is Energy?
It is the stored ability to do work.
Product of the force acting on an object and the distance travelled parallel to the force
## Footnote
Energy can exist in various forms such as kinetic, potential, thermal, and more.
35
What is Work Done?
Product of a force & the distance moved in the direction of the force.
## Footnote
Work is measured in joules.
36
Define Gravitational Potential Energy.
Energy stored due to height/position of mass.
## Footnote
It is calculated using the formula PE = mgh, where m is mass, g is gravitational acceleration, and h is height.
37
What is Internal Energy?
It is the total of the microscopic kinetic & potential energies of particles of a material.
## Footnote
Internal energy is a key concept in thermodynamics.
38
Define Kinetic Energy.
Energy of an object due to its motion.
## Footnote
Kinetic energy is calculated using the formula KE = 1/2 mv², where m is mass and v is velocity.
39
What is Power?
Rate of work done.
## Footnote
Power is measured in watts.
40
What is Elastic Potential Energy?
Energy stored due to deformation or change in shape of an object.
## Footnote
Common examples include springs and rubber bands.
41
What is Efficiency?
The fraction of the useful power output obtained from the total power input.
## Footnote
Efficiency is often expressed as a percentage.
42
Define Brittle Materials.
Materials which do not undergo plastic deformation.
## Footnote
They break suddenly when the stress exceeds a certain limit.
43
What does Hooke's Law state?
Force/load is proportional to extension/compression if proportionality limit is not exceeded.
## Footnote
It applies to elastic materials within their limits.
44
What is Ultimate Tensile Strength?
The maximum value of stress that an object can sustain before it breaks.
## Footnote
It is a critical factor in material selection.
45
Differentiate between Transverse and Longitudinal Waves.
Transverse waves have vibrations that are perpendicular to the direction of energy travel, while longitudinal waves have vibrations that are parallel.
## Footnote
Transverse waves include light waves, while sound waves are longitudinal.
46
What is Wavelength?
Distance moved by wave energy / wavefront during one cycle.
## Footnote
It is the minimum distance between two points with the same phase.
47
What is Frequency?
Number of oscillations per unit time (not per second).
## Footnote
Frequency is measured in hertz (Hz).
48
What is Amplitude?
Maximum displacement of a particle in the wave.
## Footnote
Amplitude is a measure of the energy of the wave.
49
What is the Doppler Effect?
Change in observed frequency when source moves relative to the observer.
## Footnote
It explains why a siren sounds different as it approaches and then moves away.
50
What is Young's Modulus?
Ratio of stress to strain.
## Footnote
It measures the stiffness of a material.
51
What is a Progressive Wave?
The transfer of energy as a result of oscillations/vibrations.
## Footnote
Progressive waves carry energy, unlike standing waves.
52
What is and what is the significance of Coherence in waves?
Two waves with a constant phase difference are said to be coherent.
## Footnote
Coherent waves are essential for interference patterns.
53
What is Strain?
Extension over original length (ratio).
## Footnote
Strain is a dimensionless quantity.
54
What is Stress?
It is the force per unit cross-section area required to stretch a material.
## Footnote
Stress is measured in pascals (Pa).
55
What happens during Necking?
Localized narrowing occurs at weak points when a sufficiently large force is applied.
## Footnote
Necking leads to the eventual breaking of the material.
56
What is Elastic Deformation?
Object returns to its original length when load is removed.
## Footnote
This behavior is characteristic of elastic materials.
57
What is Plastic Deformation?
Wire/body object does not return to its original shape/length when load is removed.
## Footnote
Plastic deformation occurs in ductile materials.
58
What is the significance of the area under a Force-Extension graph?
It is the work done in stretching a material.
## Footnote
The area represents the elastic potential energy stored by the material.
59
60
What is the Principle of Superposition?
When two waves of the same frequency/wavelength travel in opposite directions, the resultant displacement is the vector sum of the displacements of each wave.
61
Define Node in the context of stationary waves.
Position along the wave with no motion / zero amplitude.
62
Define Antinode in the context of stationary waves.
Position along the wave with maximum amplitude.
63
What is Constructive Interference?
When two waves meet, resulting in a displacement that is the vector sum of individual displacements, forming alternating maxima.
64
What is Destructive Interference?
When two waves meet, resulting in a displacement that is the vector sum of individual displacements, forming alternating minima.
65
What does Fringe Width/Separation refer to?
The separation between one bright fringe and the next bright fringe.
66
What are the properties of a Stationary Wave?
Does not transfer energy, amplitude varies along its length, and neighboring points vibrate in phase.
67
What is Diffraction?
The spreading of waves as they pass through gaps or around edges.
68
What is a Diffraction Grating?
An optical component with a pattern that disperses light into its constituent wavelengths.
69
What is Refraction?
The change in direction of a wave due to a change in speed.
70
What is the SI unit of Electric Current?
Ampere.
71
Define Charge in electrical terms.
It is the amount of electric charge that passes a point when a current of 1 Ampere flows for 1 second.
72
What is the SI unit of Charge?
Coulomb.
73
What does Ohm's Law state?
The current through a metallic conductor is proportional to the potential difference across it, provided temperature remains constant.
74
What is Potential Difference?
Energy converted from electrical to other forms of energy per unit charge that passes through it.
75
What does Quantised mean in the context of charge?
Charge exists in discrete amounts, meaning charge on carriers is quantised.
76
What is Resistance?
The ratio of potential difference over the current for an electrical component.
77
Define Resistivity.
The resistance of a wire of a particular material for unit length.
78
What is a Thermistor?
A specific type of resistor that changes resistance with temperature.
79
What is the unit of voltage?
Volt.
80
What does E.m.f stand for?
Electromotive Force.
81
What is Internal Resistance?
Resistance within a power source that causes energy loss.
82
State Kirchhoff's 1st Law.
The sum of currents into a junction equals the sum of currents out of the junction based on principle of conservation of charge
83
What is Kirchhoff's 2nd Law?
The sum of e.m.f's equals the sum of potential differences around a loop/circuit. Based on the principle of conservation of energy
84
What does the Law of Conservation of Charge state?
Charge cannot be created or destroyed.
85
When does a battery deliver maximum power to a circuit?
When the load resistance of the circuit equals the internal resistance of the battery.
86
What is a Potentiometer?
An arrangement used to compare e.m.fs of two sources.
87
88
What is an Alpha particle?
Either helium nucleus OR particle containing two protons and two neutrons with mass 4u.
89
Define Baryon.
A type of hadron particle that is made up of three quarks (e.g. proton and neutron).
90
What produces and What is a Beta Particle?
Produced due to weak nuclear force/interaction. B-particles are fast moving electrons with a range of speeds up to 0.99c.
91
What is Gamma radiation and is wavelength?
y- radiation is part of the electromagnetic spectrum with wavelengths between 10^(-11) m and 10^(-13) m.
92
What is Radiation's behavior in electric/magnetic fields?
Radiation can be deflected in electric/magnetic fields, and absorbed by thin paper or few cm of air.
93
Rank ionising power of radiations
Strongest is alpha followed by beta then gamma
94
What is a Hadron?
Class of heavy particles made up of quarks held together by strong nuclear force.
95
Define Isotopes.
Atoms (same element) which have the same proton number, but a different nucleon number.
96
What is a Meson?
A type of hadron particle that is made up of two quarks.
97
What is Nucleon number?
The number of protons together with the number of neutrons in the nucleus is called the nucleon number (or mass number) A.
98
What is Proton Number?
The number of protons in the nucleus of an atom (aka atomic number) Z.
99
What are the three sub-atomic particles that make up the simple model of the atom?
* Proton (positively charged)
* Neutron (uncharged but equal in mass to proton)
* Electron (negatively charged & much smaller in size & mass)
100
Define momen of couple/torque of couple
Product of the force and the perpendicular distance between the two forces of equal magnitude but opposite direction
101
Def. Fundamental particle
A particle that cannot be split up into anything smaller
102
Name the type of particle that is fundamental
Lepton
103
Define random in radioactive process
impossible to predict and each nucleus has the
same probability of decaying per unit time
104
Define spontaneous in radioactive process
not affected by external factors such as the presence of other nuclei, temperature and pressure
