Potential
Difference
If
you were an electron you would have 'charge' as well as 'mass'. You would
not be very bothered by the ups and downs in this dimension because the
force of gravity does not have a very big effect on you.
Click
here for the calculation
Don't worry if it looks hard, it is hard maths (not needed until
A level)... just look at the answer!
Scientific Model
A scientific model
is like a scientific parable.... whereas a parable is an earthly story
with a heavenly (spiritual) meaning, a scientific model is an earthly
description in everyday terms with a deeper scientific meaning. Just
as the analogy of a parable can't be taken too literally, so the model
can't.... but its basic features help us to understand how something
behaves.
A Scientific
Model for Electric Potential
The fact that you
are charged makes you susceptible to changes in something we call electric
potential gradient (a type of electrical slope). The bigger the change
in gradient (steeper the 'electric slope') the bigger push you experience
from the electric force.
You therefore have
to think of potential difference as an 'electric slope' that charges
run down (or up... if they are of opposite charge!).
- the bigger the
potential difference the 'steeper this slope' and therefore the bigger
the force or push they receive.
- the bigger the
charge on the particle the more charge moves each time therefore the bigger the current.
- the bigger the
potential gradient for an electron in a wire the faster it moves, so
the bigger the current flow (as current is rate of flow of electrons
in a wire)
The voltmeter
This is an instrument
for measuring potential difference. It measures the difference in electrical
height between to levels of electric potential. Each of these are in
volts, so it measures potential difference in volts.
Try these questions:
Q1. A component has a potential drop of 4.0 V across it. This makes a current of 0.25A flow through it. What current will flow if the drop is increased to 8.0 volts?
Q2. A component has a potential drop of 3.0 V across it. This makes a current of 0.15 A flow through it. What potential drop must be across the component if the current flowing through it drops to 0.05 A?
Click here for the
answers
NOW LOOK AT POTENTIAL
DIVISION - IT TAKES THE TOPIC FURTHER