Small PD small current, Larger PD larger current.
The amount of current depends on E(PD) & R.
If there is a potential difference in a conductor, there will be a current. But if the p.d is small, or the resistance is high the current will be small.
there should be potential difference across a device. it may be small or large.
No a few nano amps will flow from a few nano volts if the impedance is about one ohm. 100 ohms however is typical impedance of devices, but a few are less than one ohm, such as fuses and circuit breakers and amp meters..
Depends on the resistance. V= IR
