physics electricity- only up to iv characteristics graphs

what is an ion

a charged atom that has a different number of protons and electrons. they can be positively or negatively charged.

atoms

they have the same number of protons and electrons and are neutrally charged.

what is charge

a property of matter (just like mass), objects can be positively, negatively charged or neutral.

like charges ,

opposite charges

like charges repel

opposite charges attract

electric field

a region in which a charged object experiences a force.

what are electric field lines?

arrows that show the electric field around an object

what would a diagram of the electrical field lines around a positive particle look like?

the arrows are perpendicular to the surface of the particle

the arrows point away form the particle

what would a diagram of the electrical field lines around a negative particle look like?

the arrows are perpendicular to the surface of the particle

the arrows point towards form the particle

what would a diagram of the electrical field lines between a positive and a negative particle look like?

arrows point form positive to negative

what would a diagram of the electrical field lines between a two of the same charged particles look like?

rules for drawing field line diagrams

• arrows always point toward a negative charge/ away from a positive charge

• field lines never cross

• the closer the field lines are the stronger the field around the object is.

if an object electrons it becomes positively charged.

if an object electrons it becomes negatively charged.

if an object loses electrons it becomes positively charged.

if an object gains electrons it becomes negatively charged.

static charge

the charge that an object acquires due to the transfer of electrons (NOT the protons/neutrons)

if an object has more electrons than protons, what is its charge?

it is negatively charged

if an object has less electrons than protons, what is its charge?

it is positively charged

what is current

the rate of flow of electrical charge

charge of a single electron

how do we measure current

ammeter

resistance of ammeters

ammeters have very low resistance so as to not affect the rate of flow of electrons around the circuit.

where do you put an ammeter to measure current?

in series

current in the circuit

current is the same everywhere in the circuit.

what is potential difference

the energy transferred to the component or the work done on it by each coulomb of charge that passes through it.

how do we measure potential difference

using a voltmeter

where do we put voltmeters in the circuit

in parallel

resistance of voltmeters

voltmeters have a very high resistance

what is resisitance

a measure of how difficult it is for current to flow through a circuit

whats the point of IV graphs

some components have a resistance that changes when the current changes. by plotting the current-potential difference (I-V) graph for a component, you can see how it behaves when the current changes.

IV graph for a fixed resistor

• current is directly proportional to p.d

• linear graph

• it is an ohmic conductor-

• ohms law- ”the current..is directly proportional to p.d across resistor”

• has a straight line through the origin

IV graph for a filament lamp

• curves away from the y axis

• non linear

• current is not directly proportional

• non ohmic conductor

IV graph for a diode

• non linear

• curves towards y-axis

• current is not directly proportional to p.d

• non ohmic conductor

• in the negative direction, the diode has very high resistance

• the current only flows one way through a diode