Electricity Flashcards
What does emf mean?
The electrical energy per unit of charge produced by the source
What is the internal resistance?
Loss of pd per unit current in the source when current passes through the source
What is lost pd?
The energy per coulomb dissipated inside the cell due to its internal resistance
Straight line graph equation for voltage to current
V=e-Ir
Equation to work out current through the cells in parallel
I/n(number of cells)
The pd across a forward biased diode
0.6
What happens to a light dependant resistor if the light intensity increases?
Resistance and pd falls
Definition of pd
Defined as the work done ( or energy transfer) per unit charge
Symbol for work done
J or W
Ohms law?
Pd across a metallic conductor is proportional to the current through it, provided the physical conditions dont change
On a graph comparing current to pd for a thermistor what temp gives a steeper gradient?
Higher temperature
What happens when a thermistor gets hotter?
Resistance falls
What is the pd across resistors in parallel?
The same
How to find the current through a resistor in parallel?
V/Rn
Total current through resistors in parallel?
Current of both added together
