S2 L2 Flashcards
scalar vs vector
scalar = size
vector = size and direction
define force
push or pull on an object resulting from interaction with another object
define weight and unit
force acting on matter due to gravity
newtons
define mass and unit
how much matter in a space
kg
newton second law
f = ma
N
kg
m/s^2
define work and unit
energy transferred when a force is applied
joules J
equation for work
force x distance
N, m
Define potential energy
When above earth surface you have potential (stored) energy
higher up = higher
potential energy equation
m x g x h
kg
N/kg (gravitational field strength)
m
kinetic energy equation
1/2 x m x v^2
kg
m/s
conservation of energy
energy can be created or destroyed, never transferred
define electron volt
amount of KE gained by a single electron when moved across a potential difference of one volt
how much is an electron volt in joules
1.6 x 10^-19J
band theory of solids
valence and conduction band
band theory of insulator
large forbidden gap
only non moving electrons in valence band
band theory of conductor
no forbidden gap
moving electrons in both bands
band theory of semiconductor
small forbidden gap
few electrons in conduction band
How to make magnetic + electric fields
Move charge at a constant speed
Define electric current
Flow of charge
Equation to current
I= q/t
Equation for resistance
R =p x l/a
What is resistance
E- encounter coulomb force from nucleus of atoms so do not move in a straight line
How does heat affect resistance
Increases
Ohms law
V=ir
