Electricity 2 Flashcards
Electrons deliver energy from
Bat to torch bulb eg))
Each electron moves around the circuit and takes a
Fixed amount of energy from the battery as it passes through it
A battery has the potential to transfer energy from its c- store if the battery is not part of a
Complete circuit
Wd by an electron is equal to its loss of energy
Work done when an electron passes through a circuit component and transfers energy
Work done per unit charge is defined as
The potential difference or voltage across component
Potential difference is defined as
The work done (or energy transfer) per unit charge
Unit of pd is volt
Volt is equal to
1 joule per coulomb
I work W is done when charge Q flows through the component, the pd across the component V is given by
V = W /Q
The emf of of a source of electricity is defined as the electrical energy produced per unit charge passing through the source
Unit of emf is volt
Work done
IV/\t
Electrical power =
P= I V
Power unit
Watt
Volt is equal to one watt per ampere
Note
Energy transfer /\ E is equal to
Work
Battery is a combination of
Cells
A diode allows current in one direction only
Referred to as its
Forward direction
Vice is reverse direction
Resistance in a thermo resistor decreases with
Increasing temperature of the thermo resistor is intrinsic such as silicon
The resistance of an light dependant resistor decreases with
\ \
vv ---|\_\_\_\_\_|---
With increasing light intensity
To measure the variation of current with pd for a component, use either a
P….
V….
Potential divider to very pd from zero
Variable resistor to vary current to a minimum
