Internal resistance and kirchoff's law Flashcards
The energy converted from electrical energy
to other forms of energy (e.g. heat) per unit charge flowing between the two points.
potential difference
Formula for electromotive force
E = I × (R + r)
Equation for ohm’s law
V = IR
State ohm’s law
the current through a conductor between two points is directly proportional to the voltage across the two points
The power dissipated in the external resistor, PR
, is given by:
PR = I^2 R
The total power generated by the cell PT
is given by:
PT = I^2(R + r)
The fraction of the total power dissipated in the external resistor is given by:
PR / PT = R / (R + r)
After prolonged use, the internal resistance of a cell ……
May increase
The increased internal resistance reduces….
maximum current that the cell can supply
Kirchoff’s first law states
the sum of the currents flowing into any point
in a circuit is equal to the sum of the currents flowing out of that point.
Formula for kirchoff’s first law
I1 = I2 + I3
What is kirchoff’s first law based on
the conservation of charge.
Kirchoff’s second law states
the algebraic sum of the e.m.f.s around
any loop in a circuit is equal to the algebraic sum of the p.d.s around the loop.
Formula for kirchoff’s second law
E = V1 + V2
Kirchoff’s second law is based on
the principle of conservation of energy.
