Nat.5 Physics - Electricity

Electricity topic for Nat 5

Conductor

Low resistance material which conducts electricity

Current

Electric charge transferred per unit time

Electric charge

A charged particle experiences an electric force when it is in an electric field

Electric field

An area where there is an electric force on a charge.

Insulator

High resistance material, does not conduct electricity

Potential Difference

The energy given to each coulomb of charge as it passes through the power supply

Electrical Power

Electrical energy transformed each second

Voltage

The energy given to each coulomb of charge as it passes through the power supply

Direct Current (D.C)

A direct current flows through the terminals in only 1 direction.

Alternating Current (A.C)

An alternating voltage supply causes an
alternating current to flow i.e. it repeatedly
changes the direction it flows through
the terminals.

Resistance

measure of the opposition to the flow of
charge in an electrical circuit

Ohm's Law

V=IR

Experiment To Verify Ohm's Law

1. Record values of current (I) from the ammeter and
Voltage (V) from the voltmeter
2. Change the resistance of the variable resistor 3 more
times and record values of I and V at set intervals.
3. Plot a graph of Voltage (y-axis) and Current (x-axis), a
straight line through zero shows that current is
directly proportional to voltage.

The Resistance of a Filament Lamp

as we increase the voltage of the supply, the current through the filament
increases which causes the filament to heat up. This in turn causes an increase in the
resistance of the filament. This causes the line to curve.

TURD

As temperature increases, resistance decreases

LURD

As light increases, resistance decreases

Series Circuits

A series arrangement of components is where they are in line with
each other, in one single loop (i.e. connected end-to-end.)

Parallel Circuits

A parallel arrangement of components is where they are connected across each
other where the current has more than one path through that part of the circuit.

Current in Parallel Circuits

Is = I1 + I2

Voltage in Parallel Circuits

VS = V1 = V2

Current In Series Circuits

Is = I1 = I2 = I3

Voltage in Series Circuits

VS = V1+ V2

Resistances in Series

𝑅𝑇 = 𝑅1 + 𝑅2 ...

Resistances in Parallel

1/Rt=1/R2+1/R1