Class 10 Science Electricity Notes
Current is the rate of flow of electrons. Electrons flow from one point to another due to the potential difference between the points.
SI Units of current = Coulomb (C)/Second
Since an electron has a charge of 1.6×1016
, so, 6×1018 electron makes a 1-coulomb charge.
The potential difference (V): It is the work done to move 1C charge from one point to another.
SI unit: Joule/coulomb.
Conductivity: Current need a medium through which an electron can be transferred. Some medium offer high conductivity like copper, silver aluminium. Some medium offer medium conductivity like nichrome, silicon etc. Diamonds, rubber do not transfer electrons. We call them non-conductive.
Resistance is the inverse of conductivity. If conductivity is high we say the medium offers less resistance to electrical conductivity. It is a property of the material.
Resistance in series: Resistance increases as we add resistors end to end. Here current remains the same throughout the circuit.
Total resistance in series = R1 +R2 + R3+…
Resistance in parallel: Resistance decreases when we add resistors in parallel. Here potential difference remains the same throughout the whole circuit.
In parallel resistor combination:
Total resistance = R1*R2*../R1+R2+…