Chapter-3|Current Electricity| NCERT 12th Physics: Kirchhoff’s Rule: Kirchhoff’s First Rule: The algebric sum of the currents meeting at a point in an electric circuit is always zero. Or The sum of current entering the junction is equal to the sum of current leaving the junction.   Kirchhoff’s Second Rule(Loop Rule, Voltage Law): “The algebraic sum […]

Chapter-3|Current Electricity| NCERT 12th Physics: Combinations of Cells Two Cells in Series: When two cells are connected in series, then total EMF of cells Eeq= E₁+E₂ and total internal resistance req= r₁+r₂   If Cells Are Connected – to – And + to + Terminal in Series:   Two Cells in Parallel: When two cells

Chapter-3|Current Electricity| NCERT 12th Physics: Relation Between Terminal Potential Difference, EMF of Cell and Internal Resistance of a Cell: Let a cell of EMF E and internal resistance r connected to an external resistance R. let a constant current I flows through this circuit.  

Chapter-3|Current Electricity| NCERT 12th Physics: Cells and Electromotive Force(EMF) of a Cell: Cells: An electric cell is a source of energy that maintains a continuous flow of charge in a circuit. Electric cell changes chemical energy into electrical energy. Electromotive Force(EMF) of a Cell: Electric cell has to do some work in maintaining the current

Chapter-3|Current Electricity| NCERT 12th Physics: Electrical Power: It is defined as the rate of electrical energy supplied per unit time to maintain flow of electric current through a conductor.   One Watt: Power of an electric circuit is said to be 1 Watt, If 1 ampere current flow in it against a potential difference of

Chapter-3|Current Electricity| NCERT 12th Physics: Electrical Energy: It is defined as the total work done W by the source of emf V in maintaining the electric current I in the given circuit for a specified time t. According to Ohm’s law   V= IR Total charge that cross the register   q=It        

Chapter-3|Current Electricity| NCERT 12th Physics: Combination of Resistors: Resistors in Series: Resistors are said to be connected in series, If the same current is flowing through each resistor, when different potential difference is applied across the combination.   Let three resistors having resistance R₁, R₂ and R₃ respectively are connected in series, let V be

Chapter-3|Current Electricity| NCERT 12th Physics: Conductance and Conductivity: Conductance: It is defined as the reciprocal of resistance of a conductor. It is expressed as   Conductivity: It is defined as the reciprocal of resistivity of a conductor.   Relation Between Current Density, Conductivity and Electric Field: