Current-potential difference graphs
1) for a filament bulb
- the line CURVES away from the axis labelled current.
- so the current is not directly proportional to the potential difference (not a straight line) : so it DOES NOT obey Ohm's Law= it is a non-ohmic conductor.
- RESISTANCE increases as the CURRENT increases.
- the resistance of the filament bulb increases as the TEMP increases -->
when the current is passed through- there are free electrons flowing through and around the metal atoms -->
as the temperature increases= metal gets hotter = the ions in the metal filament vibrate faster and gain energy=
which means they resist the passage of electrons through the filament more.
and therefore results in an INCREASED RESISTANCE- (shown…