PHYSICS FLASHCARDS

FORMULAS

What is Temperature?

• Average amount of kinetic energy of the particles within a system

What is the kinetic particle model of matter?

• Is often a diagram which shows the change in temperature and how it affects the different stage of matter and its phase changes.

• The tiny particles in matter consists of random movements of particles. The state of matter affect the particles movement and arrangement.

What is thermal energy and internal energy? What happens when it increases?

• Thermal energy is total amount of kinetic energy from all the particles within a system.

• Internal energy is the total amount of both kinetic and potential energy of the particles within the system  

• this causes an increase in temp and phase changes

What is heat and what is kinetic energy within a particle?

 

• Heat is the transfer of energy from one object to another often from a cold to hot object.

• Kinetic energy is the energy derived from the movement of particles

What is conduction, convention and radiation?

 

• Conduction is the transfer of thermal energy  when particles collide often in solids,

• Convention is the transfer of thermal energy through fluid movements often in liquids and gases,

• Radiation is the transfer of thermal energy through waves   

Why does temperature remain constant during a phase change?

• Energy is used for the separation of particle rather than increasing the speed of the particles movement.

What is the specific heat capacity

• Specific heat capacity is the amount of energy required to increase the temperature by 1°C or 1K of a 1kg substance.

What does a high and low specific heat capacity indicate?

• A high specific heat capacity indicates a larger amount of energy required to increase temp - producing a slower reaction of heating and cooling.

• A lower specific heat capacity indicates less amount of energy required to increase temperature - allowing a faster reaction for heating and cooling.

What does each variable in the formula: Q=mcΔT? how to calculate ΔT?

• Q= Heat/energy transfer (J)

• m = Mass (kg)

• c = Specific heat capacity (J kg^-1K^-1)

• ΔT = Change in temperature (K or °C).

• ΔT = ΔT_{final -} ΔT_inital

In a specific heat capacity, why might the values differ? Provide 3 reasons.

• Heat loss

• Limitations in the equipment

• Inaccurate measurements

What is a phase change? What happens to an internal energy’s phase change?

• Physical process where the state of matter changes between either solid, liquid or gas.   

• Where the transferred energy (either in or out) of a substance changes the particle’s poteintal energy

What is specific Latent heat (L)? What does each variable in the formula indicate?

• Amount of energy required to change state of a substance at 1kg without changing its temperature.

• Q = energy transfer (J)

• m = mass (kg)

• L = specific latent heat (J kg^-1)

What is Gravitational Force?

• An attractive invisible force acting between two objects containing mass pulling the objects with mass together.

What is the acceleration? and the formula for average acceleration?

• Rate of change of velocity over time

• a = Δv/Δt

What is the SUVAT formula (No u)?

s = vt-1/2at²

What is the SUVAT formula (no a)?

s=1/2 (v-u)t

What is electromagnetic force? (both opposite and same)

• Type of attractive force acting between oppositely or same charge particles either.

• Opposite causes it to attract each other

• While the same particles causes it to repel against each other.

What is a strong nuclear force?

• The strongest nuclear force

• Type of force holding the protons and neutrons in the nucleus

What is a weak nuclear force?

• A weak nuclear force alters the identity of the particles resulting in beta decay.

Difference between fission and fusion: function, releases, occurrence and chain reaction? (in the context of both particles and nucleus)

Fission:

• Large particles/unstable nucleus is broken apart into tinier versions

• Releases neutrons and energy (mass is converted to energy).

• Occurs when a heavy nucleus takes in a slow-moving neutron

Fusion:

• Is where small atoms/particles/ two nuclei’s are pulled together making a larger atom or nucleus

• Releases a great amount of energy

why does fusion release a greater amount of energy than fission?

• Fusion has a greater amount of mass being converted into energy than fission

What is Thermal Equilibrium? Provide an example

• Thermal equilibrium is where all the objects are in equal temperature to each other, causing no net heat flow.

• Example - spoon in a hot chocolate

Why does thermal energy transfer occur? What happens to the particle kinetic energy when thermal equilibrium is reached?

• when objects are in contact with each other, with either one or all in different temperatures. This results in the energy to move from a higher temp to a lower temp – allowing thermal equilibrium to be reached.

• Equal energy is reached due to all objects being in equal temp to each other.

What is zero law of thermodynamics?

• When all three objects are in equilibrium with each other.

What is the law of conservation of Energy and Electric charges? Provide an example

• Energy cannot be destroyed nor created, only changed or transferred.

• Electric charges cannot be destroyed nor created, only transferred.

How does thermal equilibrium relate to the laws of thermodynamics?

• When all three objects are in equal temperature to each other, the net transfer of energy stops – thermal equilibrium despite particle always being in a constant random movement.

What is the first law of thermodynamics? What is the formula? and what does the law support?

• When energy is added or when work is done either on or by the system it results in a change in internal energy: ΔU = Q + W

• This shows the conservation of energy.

How can thermal energy do mechanical work? why does some of the energy get lost into the environment?

 

• By work performed by the system through particle’s collision or movement.

• Energy can be lost into the system’s surroundings due to friction, excess of energy or resistance.

What happens to useful energy in a system, when heat is lost to enivornment?

• The amount of usable energy declines. As more energy is being transferred/lost into the surroundings limiting its useful forms.

What is efficiency? what does a low and high efficiency indicate?

• Ratio measurement of the amount of input energy being converted and transferred instead as useful output energy.

• Low  efficiency = large amount of lost energy to the environment

• High efficiency = small amount of energy lost to its environment

What is the formula for how to solve heat transfer efficiency problems?

• n = energy output/energy input

What is the difference between distance and displacement?

• Distance - Total amount travelled. Scalar quantity and no direction

• Displacement - Point A to Point B. vector quantity and direction

What are Newton’s 3 laws?

Law 1: An object will remain at constant linear speed or in stationary position until external net force is applied onto the object.

Law 2: Acceleration of the object equals to the sum of the net force divided by the mass. Heavy reliance on force and mass

Law 3: amount of force and time object A applies onto object B (when pushing or pulling in a linear direction) is the same amount of force and object B applied back onto object A simultaneously, however in the opposite linear direction.

What are nuclides? Why do protons in nuclides repel against each other?

• atom defined by the mass number, (Number of protons and neutrons).

• repel due to all being positively charged experiencing a electrostatic repulsion.

What is Coulomb?

• A measurement (unit) of an electric charge

• Electrostatic repulsion between protons

What does a strong nuclear charge indicate?

• indicates a high attractive force between the protons and neutrons

What affects and determines nuclear stability?

• ratio of neutrons to protons

• nucleus size

• nuclear force

• electrostatic repulsion

What is radioactive decay?

• Natural process where an unstable nucleus removes its radiation to become stable.

Why does a heavier nuclei require more neutrons than protons?

• Neutrons increase nuclear force without adding electrostatic repulsion (the repulsion makes the nucleus less stable).

what is the difference between Alpha, beta and gamma radiation? including each charge, mass, penetration and ionisation?

Name:	Mass and charge:	Function: to make it stable	Ionisation:	Penetration:
Alpha decay	Contains a helium nucleus (charge of +2 and mass of 4)	Removes mass and charge to make nucleus and nuclei stable.	Low	High
Beta (+) decay	Charge of -1 and a mass of 0,	Decreases neutrons, and increases protons.	Medium	Medium
Beta (-) decay	Charge of +1 and a mass of 0	Changes proton into neutron	Medium	Medium
Gamma	Charge and mass 0	Releases additional energy	Very high	low

when does Alpha, betas and gamma occur? What is its main achievement?

• Alpha - unstable and heavy nuclei that requires both mass and atomic number to be reduced.

• Beta (β⁻) - too many neutrons

• Beta (β⁺) - too many protons

• Gamma - releases excess energy

• change the unstable nuclide into a stable nuclide

What is half-life? Does each radionuclide change?

• number of undecayed nuclides that halves

• each radionuclide remains constant

What does each variable stand for in the decay formula? How to calculate n?

• N = number of undecayed nuclei

• N₀ = initial number of nuclei

• n = number of half-lives elapsed. elapsed time/half-life

what does an electric volt indicate?

• an electron has gained energy (J) by moving through a voltage (potential difference) of 1volt.

what is artificial transmutation?

A man-made deliberate process by changing a nuclide into a isotope or different element through the alter in neutrons, protons or alpha particles.

What is mass defect?

Weight lost/disappeared from difference between the actual mass of nucleus and the individual mass of the protons and neutrons.

Example: ingredients for a cake = 2g, when baked = 0.9g

(1)what is binding energy? (2)what does binding energy per nucleon mean? (3) what does a high binding energy suggest?

• (1) is energy created when mass defect is converted into energy using the mass-energy equivalent formula

• (1) energy that holds nucleus together

• (2) average amount of binding energy per nucleon. calculated by = total binding energy/number of nucleons

• (3) more nucleus stability

What is the mass-energy equivalent formula and what does it show?

• Δe = ΔMC²

• E = energy absorbed or released (J), M = mass defect (kg), c =speed of light (3×10⁸ ms^-1)

• shows how mass in a small amount can be converted into energy in a large amount.

why does nuclear reactions release a lot of energy?

• despite a small mass defect, the energy can still be converted into a large amount, due to the relatively large value of c²

what is electric charge? what does it cause?

• one of the properties of matter

• either positive or negative

• causes electric currents and forces etc

(1) What is a electric current? and (2) what does it carry in metal conductors? (3) what is the formula and unit?

• (1) electric charges in a rate of flow

• (2) it carries electrons

• (3) formula: I = Q/t. I=current (A), Q=charge (C), t= time (s)

• (3) unit = Ampere (A)

What does the law of conservation of electric charge indicate in a electrical circuit?

• The amount of charge that enters the circuit is the same that leaves at the circuit -supports the law

(1) what are voltages (potential difference)? (2) what is the formula for potential differences? and (3) the amount of one volt?

• An electrical pressure or pusher forcing the electric charges to flow through the conductors

• V= W/Q. V= Potential difference (V), W= Energy transferred (J), Q = charge (C)

• 1V = 1J of energy of each coulomb of charge

how is electrical potential difference created? and why does charge move through potential differences?

• through the separation of positive and negative charges

• provides energy that results in the flow of charges

What is electrical power? and what is the equation? what does a high and low rate indicate?

• rate of the transfer or conversion of electrical energy

• P = W/t. P = Power (W), W = energy (J), t =time (s)

• more energy is being transferred or converted every second

what is resistance? what is it measured by? how is it caused?

• level of difficulty for electricity to flow through a material

• ohm Ω

• collision of electron movement and in conductors - atoms and ions (Stops or slows down movement of electrons)

what happens to the current if the resistance increases or decreases while voltage remains constant?

• resistance increases = current decreases

• resistance decreases = current increases

what happens if to the current, if the voltage increases and resistance remains constant?

• current increases directly proportional to voltage

What happens to the resistance if voltage and current both double?

resisitance remains same given formula: R = V/I

what is Ohm’s law? and the formula?

• Describes the connection between current, voltage and resistance

• V=IR. V=potential difference (V), I = Current (A), Resistance (Ω)

What is a ohmic resistor?

• A type of resistor that remains constant at temperature despite voltage and current changing - obeying the Ohm’s law

what is a non-ohmic resistor?

• A type of resistor which changes as temperature, current and voltage change - not obeying ohm’s law

what does the current-voltage graph (I-V) of a ohmic and non-ohmic resistor show?

• ohmic: a linear line - showing a proportional relationship

• non-ohmic: a non-linear line - showing an inproprtional relationship

how to distinguish between ohmic and non-ohmic?

• ohmic: if the graph is linear or the value of R remains constant

• non-ohmic: graph is not linear and value of R does not remain constant

What is power dissipation in a resistor? When does it occur?

• Where electrical energy is converted into other forms of heat or energy

why do resistors dissipate power?

• through collision inside resistors of electrons with atoms, transferring the electrical energy into thermal energy

what are each of this circuits? name and function

1. resistor - limits electrical current flow

2. voltmeter - measures the two points of an electrical potential difference

3. Ammeter - measures electrical current flow in a circuit

4. cell - a single unit of electrical energy

5. battery - combination of two cells provides a higher voltage

6. switch (open) - shows a break in circuit stopping flow

7. light bulb - converts electrical energy into light

what is a simple circuit? What is the formula?

• Circuit where all components are connected in one path - same current flow throughout each component

• I_total = I₁ =I₂ = I₃ =I₄…

What is happens to the voltage in a series circuit? what is the formula?

• Total amount of voltage is divided among the components.

• formula: V_total = V₁ + V₂+ V₃…

How to calculate equivalent resistance in a series circuit?

R_total = R₁ + R₂+ R₃…

What happens to the total resistance when more resistors is added into the series vs the added in a parallel?

• The total resistance increase increasing the resistance in the flow of the current

• The total resistance due to an increase in pathways for current to flow

What is a parallel circuit? What happens to the voltage in a parallel circuit?

• A circuit where the components are all connected together across branches (multiple paths)

• The potential difference for each branch is the same

• V_total = V₁ = V₂ =V₃…

What happens to the current in a parallel circuit?

• The current is divided among the branches

• I_total = I₁ + I₂ + I₃…

What is the formula to calculate equivalent resistance in a parallel circuit?

• 1/R_total = 1/R₁ +1/R₂… +1/R_n

Main differences between series and parallel circuits?

Series circuit:	Parallel circuits:
-              One pathway	-              Multiple pathways
-              Same current	-              Current divides
-              Voltage decreases	-              Same voltage across all branches
-              When resistors are added, total resistance increases	-              Resistance decreases when resistors are added

What is a series/parallel circuit?

• contains both sections and qualities of series circuit and parallel circuit

What is a vector quantity? Provide 3 examples

• A physical quantity that contains both direction and magnitude.

• Displacement, momentum and velocity

Difference between speed and velocity and the formulas

speed - scalar and is the rate of change of distance. Speed = distance/time

Velocity - vecotr and rate of change in displacement. v = Δx/Δt

How does the direction affect the acceleration and speed?

positive direction = negative acceleration = speed slows down

negative direction = negative acceleration = speed increases

What is a resultant vector?

• A single vector that does the same effect as another vector with two or more combined vectors.

(1) What does a displacement-time graph show? (2) What does a gradient (slope) represent and (3) when its steeper? (4) and its formula?

• (1) Object’s displacement changing over time

• (2) velocity

• (3) greater velocity

• (4)Gradient = ΔDisplacement/Δtime

what does the area under a velocity-time graph represent? and what does a positive, horizontal and negative velocity line indicate in the graph for acceleration?

• Displacement

• horizontal - constant velocity - acceleration 0

• positive - positive acceleration - velocity increases in positive direction

• negative - negative acceleration - velocity decreases in negative direction

what is a acceleration-time graph show? What does the are under the acceleration-time graph show?

• An object’s acceleration changing over time

• Change in velocity (Δv)

What does a horizontal line on, above and below the time axis in the acceleration-time graph indicate?

• above - positive constant acceleration

• on - zero acceleration - velocity is constant

• below - negative constant acceleration

What is a intercept in a motion graph?

• A line, curve or point that crosses the axis

What are the maximum and minimum lines of best fit?

• estimating the possible range of values that the uncertainty falls within from the maximum to minimum values.

what does uniform acceleration mean? what does each variable in the SUVAT formula represent?

• A motion’s acceleration is constant

• s= displacement (m)

• u=initial velocity (m/s)

• v=final velocity (m/s)

• a=acceleration (m/s²)

• t= time (s)

What acceleration does an object experience during a free fall (disregarding air resistance). how can acceleration due to gravity be calculated?

• A acceleration downwards at a constant 9.8m/s²

• Caculate a

What is a free fall?

• An object’s motion where only gravity is the force acting upon it.

What is force measured in? what is the formula for weight?

• Newtons (N)

• Force is a vector quantity

• W = mg. W= weight (N), mass (kg), g=9.8m/s²

What is normal force, tension, friction, drag and applied forces acting on objects?

• Normal force - upward push from a surface onto an object to stops it from falling through.

• Tension - a force of pul transmitting through cables, strings or ropes.

• Drag - a force of resistive by a fluid (water or air) to oppose the object from moving through it

• friction - opposing force of motion between surfaces in physical contact

• Applied force - external force (push or pull) that is applied onto an object from another object

What is a free-body diagram? what forces does it include?

• A diagram of a object or person showing how their surrounding forces act upon them. this is represented through different sized arrows (Indicates magnitude) pointing in a certain direction - indicating direction.

• Forces include: weight, normal force, tension (if applied), drag (if applied), friction (if applied) and applied force (if applied)

What is resultant force (net force)? How to calculate in same direction vs opposite direction?

• A force equaling to the sum of all forces acting upon the person or object

• same direction - add together = Net force

• opposite direction - subtract from direction with largest force (subtract smaller force from bigger force) = Net force

Mass vs weight

mass - total constant amount of matter within object

weight - amount of mass with gravitational force (changes depending on field of strength) acting upon

(1) What is momentum? (2) what quantity is it? (3) what affects momentum? (4) what is the formula?

• Amount of motion an object contains

• vector

• mass and vector

• p=mv. p =momentum (kgms^-1), m=mass (kg), v= velocity (ms^-1)

what is impulse? what is the formula for impulse? What does the area under a force-time graph represent?

• change within momentum due to an external force acting upon it over a length of time

• J = Δp

• Impulse

What is the equation and the law of conservation of momentum? when can it be applied?

• ∑P_before = ∑P_after

or

• m₁v₁+m₂v₂ = m₁v₁+m₂+v₂

• Applied when no net force is acting upon the objects

Elastic collision vs inelastic collision?

• elastic collision - collision when the object collide and bounce/pull apart - not sticking together. Kinetic energy and momentum are conserved

• non-elastic collision - collision when the object collide and do not bounce/pull apart resulting in the objects to stay stuck together. Kinetic energy is lost and momentum is conserved

What is mechanical work?

• Work done onto an object resulting in a displacement move this is caused by force

What is work done? and what is the formula?

• The transferred energy due to force.

• W = Fs. W=work done (J), F=Force (N), s=displacement (m)