IB Physics B1 Chapter

Formulae and Definitions

Formula for densit

p=\frac{m}{V}

SI Unit for density

kilograms per cubic meter (kgm^-³)

Definition for density

the mass of an object divided by its volume

Definition for temperature

a measure of the average kinetic energy of the particles in a substance, indicating how hot or cold it is.

Definition for kinetic energy in terms of temperature

the energy an object possesses due to its motion, which is directly proportional to its temperature. Higher temperatures correspond to greater average kinetic energy of the particles in a substance.

Formula for average random translational kinetic energy of a gas particle

\overline{E_{k}}_{}=\frac32k_{B}T (Kb is the boltzmann constant = 1.38 × 10^-23)

Definition for internal energy

the sum of total random kinetic energies and total potential energies of all the particles inside it

Formula for Internal Energy

IE=E_{k_{total}}+E_{p}_{total}

3 principle ways of thermal energy transfer

1. Conduction, 2. Convection, 3. Radiation

Definition for Conduction

the transfer of kinetic energy between particles

Formula for thermal conduction

\frac{\Delta Q}{\Delta t}=kA\cdot\frac{\Delta T}{\Delta x}

Definition for convection

the transfer of thermal energy because of the movement of a fluid due to changes in density

Definition for Thermal Radiation

the transfer of energy through electromagnetic waves, emitted by all objects based on their temperature.

Perfect black body

A term we use to describe an object which has a surface which absorbs all of the infrared and light that falls on it

Formula for power emitted from a black body

P=\sigma AT^4

Wien’s displacement law

\lambda_{\max}T=2.9\cdot10^{-3}mK

Formula for Luminosity

L=\sigma AT^4

formula for apparent brightness

b=\frac{L}{4\pi d^2}

Definition for apparent brightness

a measure of the intensity of the radiation from the start which reaches earth

Formula for intensity

I=\frac{P}{A}

SI Unit for Intensity

Wm^-2

Q = mc\Delta T cific heat capacity, c

the amount of energy needed to raise the temperature of 1kg of a substance by 1kg

Formula for thermal energy transferred

Q = mc\Delta T

Definition for Latent Heat

the amount of energy transferred when 1kg of the substance changes phase at a constant temperature

Formula for latent heat

Q = mL