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User:FreeT/Physics Equations

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Please do not edit this page. This is part of FreeT's space to type thoughts to use for a later time, giving a higher quality to the finished article.
This subpage is about physics equations on the Irish Leaving Certificate sylabus. You may of course copy material from here, just please don't edit it. If you can come up with some good mnemonics, please enter them.


*Edit*
From the 2010 Leaving Certificate on, new log tables will be supplied for the exams which will include most of the following formulae. Still, I'll finish the list for anyone who would like to learn them, or needs to learn them for a different exam.


Reflection of Light from Spherical Mirrors

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Reflection of light in a spherical convex mirror.
Formula Abbreviations Mnemonic
u - distance from the object to the mirror

v - distance from the image to the mirror
f - focal length
nb, v is + for real image
v is - for virtual image
f is + for concave mirror
f is - for convex mirror

m - magnification

u - distance from the object to the mirror
v - distance from the image to the mirror

over under



Refraction

[edit]
Refraction in a Perspex (acrylic) block.
Formula Abbreviations Mnemonic
i - Angle of incidence

r - Angle of refraction
n - Refractive Index between the two media

Being rare gets presidence over being dense
For any two media x and y

n - Refractive index between the two media

n - Refractive Index of medium Real truth presides over apparent truth anyday
n - Refractive Index of medium The vacuum is always lighter, so it rises to the top
n - Refractive Index

C - Critical angle

Lenses

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Convex lens in action
Formula Abbreviations Mnemonic
u - distance from object to lens

v - distance from image to lens
f - focal length
where:
u is always +
v is + for a real image
v is - for a virtual image
f is + for a convex lens
f is - for a concave lens

m - magnification

v - distance from image to lens
u - distance from object to lens

P - power of lens

f - focal length

power of lens is measured in per metres
P - overall power of combination of lenses

P1 - power of first lens
P2 - power of second lens

f - overall focal length of combination of lenses

f1 - focal length of first lens
f2 - focal length of second lens
where:
f is given a + for a convex lens and a - for a concave lens.

Temperature

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Formula Abbreviations Mnemonic
t(C) = t(K) - 273.15 t(C) - temperature in degrees Celsius

t(K) - temperature in degrees Kelvin

To serve three-period, single fights.

Small number = Big number - a lot.


Quantity of Heat and Heat Transfer

[edit]
Formula Abbreviations Mnemonic
Q - heat energy

m - mass (kg)
c - specific heat capacity
- change in temperature

MCAT
Q - heat energy

m - mass (kg)
l - specific latent heat

Waves and Wave Motion

[edit]
Surface waves in water
Formula Abbreviations Mnemonic
T - time for one cycle to pass a point

f - frequency (hz) or cycle per second

c - velocity of wave

f - frequency
- wavelength

f' - observed frequency

f - actual frequency
c - speed of wave in the medium
u - speed of source
nb.
u is negative if source is moving away from observer.

Vibrations and Sound

[edit]
Formula Abbreviations Mnemonic
I - sound intensity

P - power
A - area

Patrick's over-Aim is an Intense miss
f - fundamental frequency

l - length
- mass per unit length
T - tension

2 Live freely is the root of tears undue.
overtone = harmonic n - any number
c = 4f (l + 0.3 d) c - speed of sound in medium

f - frequency of note emitted
l - length of closed pipe
d - diameter of pipe

Static Electricity

[edit]
Formula Abbreviations Mnemonic
Q1 and Q2 = charges

F = force between charges
d = distance between charges

Queens over four pies eating a square dinner = very forceful.
E = Permittivity of medium

Er = Relative permittivity of medium
Eo = Permittivity of a vacuum

E = Electric Field Strength

F = Force
Q = Charge

'Free and easy but queasy' triangle

Potential Difference and Capacitance

[edit]
Formula Abbreviations Mnemonic
W = QV W = Work Done

Q = Charge/Number of Coulombs Transferred
V = Potential / Voltage

Where is the Queen's Vulture?
C = Capacitance of a conductor

Q = Charge
V = Potential / Voltage

'Queens Catch Vultures' Triangle
C = Capacitance of a conductor

d = Distance between plates
E = Permittivity of the dielectric
A = Area of overlap of the plates

W = Energy stored in a charged capacitor

C = Capacitance of a conductor
V = Potential / Voltage
nb. This formula gives the average work done
It can not be derived by combining W=VQ with Q=VC.

Similar to in log tables.

Current and Charge

[edit]
Formula Abbreviations Mnemonic
Q = It Q = Charge gone past

I = Steady current
t = time

Similar to "quit".

Electromotive Force and Potential Difference

[edit]
Formula Abbreviations Mnemonic
W = QV W = Energy given out

Q = Charge gone past
V = Potential / Voltage

Where is the Queen's Vulture?
VI=P V = Potential difference between two points

I = Current flowing between two points
P = Power dissipated between two points.

Very Important Person

Resistance, Current, Voltage

[edit]
Formula Abbreviations Mnemonic
R = Resistance

V = Potential / Voltage
I = Current

Ronaldo is Very over Inphasised.
p = Resistivity of the material in the conductor

R = Resistance
A = Cross-sectional area
l = Length

Pink Light is Readily Accepted
l = Length

p = Resistivity of the material
d = Diameter of wire
R = Resistance

4 Pirate Leaders are Raiding Pies at the square Dance
When a wheatstone bridge is balanced:

P = Power

I = Current
R = Resistance

Twinkle, twinkle little star, Power = I squared R

Series Circuit

[edit]
Formula Abbreviations Mnemonic
R = Total resistance

R1, R2 and R3 are separate resistors in series

A1, A2 and A3 are three ammeters in series
V = Total voltage

V1, V2 and V3 are three batteries in series

Parallel Circuit

[edit]
Formula Abbreviations Mnemonic
R = Total resistance

R1, R2 and R3 are separate resistors in parallel

A1, A2 and A3 are three ammeters in parallel
V1, V2 and V3 are three batteries in parallel

Effects of an Electric Current

[edit]
Formula Abbreviations Mnemonic
W = Heat given out by a wire

I = Current
R = Resistance
t = Time

Speed, Displacement and Velocity

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Formula Abbreviations Mnemonic
v = Average velocity

s = Displacement
t = Time taken

Acceleration

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Formula Abbreviations Mnemonic
a = Average accleration

v = Final velocity
u = Initial velocity
t = Time taken

a = Average accleration

v = Final velocity
u = Initial velocity
t = Time taken

Given in log tables
a = Average accleration

s = Displacement
u = Initial velocity
t = Time taken

Given in log tables
v = Final velocity

u = Initial velocity
a = Average acceleration
s = Displacement

Given in log tables

Force, Mass and Momentum

[edit]
Formula Abbreviations Mnemonic
F = ma F = Force

m = Mass
a = Acceleration

p = mv p = Momentum

m = Mass
v = Velocity

F = Force

m = Mass
v = Final velocity
u = Initial velocity
t = Time

m1 = Mass of object 1

u1 = Initial speed of object 1
v1 = Final speed of object 1
m2 = Mass of object 2
u2 = Initial speed of object 2
v2 = Final speed of object 2

Pressure and Gravity

[edit]
Formula Abbreviations Mnemonic

i.e.

p = Density

m = Mass
v = Volume

"Monkeys Drink Vodka" Triangle
P = Pressure

F = Force
A = Area

Given in log tables
P = pgh P = Pressure

p = Density
g = Gravity
h = Depth (height)

Given in log tables

Magnetic Fields

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Formula Abbreviations Mnemonic
F = Force

B = Flux density of field
I = Current in conductor
L = Length of conductor

Bills are forceful
F = Force on particle

q = Charge on particle
v = Speed of particle
B = Flux density of field

= Magnetic Flux

B = Magnetic Flux Density
A = Area

Induced emf E = (Final flux - Initial flux) / (Time taken)