This post contains all the important formulas that you need for GCE O Level Physics. (Equivalent to American High School Diploma) If you do not recognise any of the formulas listed here, you should go review the respective topic. For definitions, please visit All Definitions Needed For O Level.

## Measurements

Physical quantity | Base SI unit |
---|---|

Mass (m) | Kilogram (Kg) |

Length ($l$) | Metre (m) |

Time (t) | Second (s) |

Current ($\text{I}$) | Ampere (A) |

Temperature (T) | Kelvin (K) |

Amount of sub. (n) | Molar (mol) |

Luminous Intensity (L) | Candela (cd) |

Number | Prefix | Number | Prefix |
---|---|---|---|

$10^{-9}$ | nano (n) | $10^{-1}$ | deci (d) |

$10^{-6}$ | micro ($\mu$) | $10^{3}$ | Kilo (K) |

$10^{-3}$ | milli (m) | $10^{6}$ | Mega (M) |

$10^{-2}$ | centi (c) | $10^{9}$ | Giga (G) |

$$\text{Reading without zero error} = \text{Reading Obtained}-\text{Zero Error}$$

## Kinematics

Average Speed, $s = \frac{\Delta d}{\Delta t}$, d is distance travelled

Average Velocity, $v = \frac{\Delta x}{\Delta t}$, x is displacement

Acceleration, $a = \frac{\Delta v}{\Delta t}$

$v = u + at$

$x = ut + \frac{1}{2} a t^{2}$

$v^{2} = u^{2} + 2 ax$

$s = \frac{1}{2} \left( u + v \right) t$

Information that you have | Equations of motion to use | ||||
---|---|---|---|---|---|

s | u | v | a | t | |

$v = u + at$ | |||||

$s = ut + \frac{1}{2} at^{2}$ | |||||

$s = \frac{1}{2} (u + v)$ | |||||

$v^{2} = u^{2} + 2as$ |

$v_{free \, fall} = \sqrt{2 gh}$

If a car is driving around a circle at a constant speed, its velocity is not constant! The car is accelerating! Why? Because velocity is a vector (has both magnitude and direction). When the car is travelling around the circle, its direction is changing constantly.

## Forces and Turning effect of Force

Newton’s First Law: A body continues to stay in its state of rest or uniform motion in a straight line as long as there is no net force acting on the body.

Newton’s Second Law: The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass.

Newton’s Third Law: For every force object A acts on object B, object B will exert an equal and opposite force on object A giving rise to reaction force.

$M = Fd$, M = moment, d = perpendicular dist. from force to pivot

Principle of moment: sum of anti-clockwise moment = sum of clockwise moment. $\rightarrow$ rotational equilibrium.

## Mass, Weight and Density

$w = mg$

$\rho = \frac{m}{V}$

## Pressure

$P = \frac{F}{A}$

$P_{fluid} = h \rho g$

Hydraulic press: $\frac{F_{1}}{A_{1}} = \frac{F_{2}}{A_{2}}$

Boyles’ law: $P_{1}V_{1} = P_{2}V_{2}$

## Work, Energy and Power

$W = Fd$

$P = \frac{W}{t} = Fv$

$E_{k} = \frac{1}{2} m v^{2}$

$E_{g} = mgh$, g = 9.81 $m \, s^{-2}$

Conservation of energy: Initial energy = final energy

## Thermal Physics

$PV \propto T$

$P_{1}V_{1} = P_{2} V_{2}$

$E = m c \Delta T$

$E_{fusion} = m L_{fusion}$

$E_{vap.} = m L_{vap.}$

Temperature can be measured using the following methods:

- Expansion of fixed mass of liquid
- Changes in resistance of a piece of metal
- Expansion of gas at constant pressure

Why is there constant temperature during melting?

- During melting, heat energy is used to weaken the attraction between the solid particles and not used to increase the kinetic energy of the particles.

When a thermometer is placed into hot water, why does the reading drops first then increase?

- The glass bulb expands before the mercury expands.

Good radiator of heat

- Black surface
- Rough surface

## Waves, Reflection and Refraction of light, Converging lens, Electromagnetic Spectrum, Sound

$v = f \lambda$

$f = \frac{1}{T}$

Law of reflection: $\theta_{i} = \theta_{r}$

Snell’s Law: $n_{1} \sin{\theta_{1}} = n_{2} \sin{\theta_{2}}$

Refractive index: $n = \frac{c}{v}$

Denser to less dense medium: Light ray bends away from normal

Less dense to denser medium: Bends towards normal

$$1 < n \left( \lambda_{\text{red}} \right) < n \left( \lambda_{\text{green}} \right) < n \left( \lambda_{\text{blue}} \right)$$

Critical angle: $\sin{\theta_{c}} = \frac{n_{2}}{n_{1}}$, $n_{2}$ is smaller than $n_{1}$

Magnification: $M = \frac{h_{i}}{h_{o}} = \frac{d_{i}}{d_{o}}$

**Note:**

- An image that is real is always inverted!
- An image that is virtual is always upright!

When a water wave moves from deep to shallow,

- wavelength become shorter
- Frequency remains the same (Freq. of water wave only depends on SOURCE)
- Speed becomes slower

Factors that affect speed of sound

- Temperature – Higher temperature = higher speed of sound
- Medium – The denser the medium, the higher the speed of sound
- Humidity – Sound travels faster in higher humidity conditions

Characteristics of Image formed on plane mirror

- Same size
- Laterally inverted
- Image is virtual

Go to the next page for more equations

This is really useful!!

It’s really helpful

It Is a very powerful instrument….

it really is and it makes it all better to understand

This is a very helpful learning tool, thanks.

Very Helping….thanks !!!

I needed application of light waves and sound waves to the society at large but it was impossible for me to find

This was really helpful for quick revision right before exams .

Good Bt No Electricity

Page 2 is all about Electricity.

DEAR,I want to print it how can I ?

I think I am on the right platform to better my physics up.

I like this. I will be buying MBs to study online.

As a young physicist I love this forum….great Albert decendants

haha

I WANT TO BE BRAVE HOW WILL I DO?

No magnetism or electricity formulas….. insufficiently done

Eat sharks

what about the electrical parts

you guys missed the entire chapter on electrical formulas

Efficiency as well

PAGE 2.

wow!!! tnxs.. d formular are jus ok..

wonderful. this is the way to promote your level in physics.

wonderful physics

Truly Physics unravels the wonders of the world we live. Yes it is wonderful

tnk you.this is very sufficient forum .

Dis is fanatasic …….very good

I like it. So helpful

Please could you make one such for Edexcel AS Physics. .

l Love it

Good Job

Very supportive????????????

I really found physics interesting after I read these

help ful

Really good! Pls include useful power formula thanks!

So helpful

It was really helpful i guess so it is useful for all my friends thanx

Thank you so much!

I have my CIE exam tomorrow, really helped a lot.

thankyou so much!

i have my cie tomorrow.

this was really helpful 😀

Great!There should be more formulas.

Hello, can you suggest formulas to be added to this list?

like formulas from specific heat capacity or latent heat or zero error or graphs of kinematics or electromagnetic spectrum

but this is still very effective i love these notes. have helped me a lot thankyou so much miniphysics

Hello! Thanks for the suggestions! They are added into the list. 🙂

It helped me save a lot of time. I copied all the formulas and practiced question using them. Finding all the formulas in one place helped me finish my revision in 2 hours, other wise it would’ve taken more than 3. Thanks a lot!

Thanks.Having my o levels tomorrow.this helped

Having my pure physics o’s tomorrow this was very helpful! HAHA only started memorising today and this was perfect

Same 🙂 good luck!

Thank you! having my o levels tomorrow :B

hey, i guess you are doing the oct/nov too this year XD, same here , we have physics paper 4 tomorrow

Any way you could upload a downloadable version?

This is very useful for revision.