Home Physics Current Electricity

Current Electricity

Electric current, flow of electric charges in a metallic conductor, drift velocity, mobility and their relation with electric current; Ohm's law, electrical resistance, V-I characteristics (linear and non-linear), electrical energy and power, electrical resistivity and conductivity, Carbon resistors, colour code for carbon resistors; series and parallel combinations of resistors; temperature dependence of resistance. Internal resistance of a cell, potential difference and emf of a cell, combination of cells in series and in parallel, Kirchhoff's laws and simple applications, Wheatstone bridge, metre bridge. Potentiometer - principle and its applications to measure potential difference and for comparing EMF of two cells; measurement of internal resistance of a cell.

Potentiometer

Potentiometer

A potentiometer is a device used to measure an unknown emf or potential difference accurately. The potentiometer is a device to compare potential differences. Since...
Wheatstone bridge

Wheatstone bridge

It is an arrangement of four resistance used to determine one of this resistance quickly and accurately in terms of the remaining three resistances. The...
Meter Bridge or slide Wire Bridge

Meter Bridge or slide Wire Bridge

It is the simplest practical application of the Wheatstone bridge that is used to measure an unknown resistance. Principle: Its working is based on the...
Kirchhoff Law

Kirchhoff’s Rules

Electric circuits generally consist of a number of resistors and cells interconnected sometimes in a complicated way. The formulae we have derived earlier for...
Distinction between EMF and Potential Difference

Distinction between EMF and Potential Difference

Distinction between EMF and Potential Difference
Combination of Resistors

Combination of Resistors- Series And Parallel

Combination of Resistors- Series The current through a single resistor R across which there is a potential difference V is given by Ohm’s law I...
Combination of cells in series

Combination of cells in series And Parallel

 Combination of cells in series When external resistance is negligible in comparison to the internal resistance, then the cells are connected in parallel to get maximum...
Effect of Temperature on Resistance

Effect of Temperature on Resistance

Temperature dependence of resistance: When temperature increases, the no. of collisions increases due to more internal energy and relaxation time decreases. Therefore, Resistance increases. Temperature Coefficient...
Color Code for Carbon Resistor

Color Code for Carbon Resistor

The first two bands from the end indicate the first two significant figures of the resistance in ohms. The third band indicates the decimal multiplier. The...
Ohm’s Law

Ohm’s Law

The electric current I flowing through a substance is proportional to the voltage V across its ends, i.e., V ∝ I V = RI, where R...