Electricity

Charge: Basic Property associated with matter due to which it produces and experiences electrical and magnetic effect.

Benjamin Franklin named the two types of charge as positive and negative.

Coulomb's Law: The force of attraction or repulsion between two point charges at rest is directly proportional to the product of magnitude of charges and inversely proportional to the square of the distance between them.

**Electric field intensity inside a charge hollow conductor is zero. charge given to such conductor remains on it surface only.

Electric Capacity: charge required to increase the potential of the conductor by unity. Q/V

Electrochemical cell: Converts chemical energy into electrical energy.

Primary Cell: Electrical energy obtained from the irreversible chemical reaction taking inside the cell. ex: voltaic Cell, Laclance Cell, Daniel Cell.

Secondary Cell: It is rechargeable cell,

Production of electricity by chemical reaction was first discovered by Allexandaro de volta in 1794. Voltic cell is named after him.

Leclanche cell is used for intermittent work, in which continuous electric energy is not required like electric bell.

EMF of leclanche cell and dry cell is 1.5 emf.

Current Electricity: Rate of flow of charge.

Its direction is the direction of flow of positive charge.

Its SI unit is ampere and it is a scalar quantity.

** A current of one ampere flowing through a conductor means 6.25 * 10^18 electrons are entering at on end or leaving the other end of conductor in one second.

Resistance: SI Unit Ohm.

Ohm's Law: V directly proportional to I

V=RI

V: potential difference, R resistance constant, I: current

Conductance: Reciprocals of resistance of conductor is called its conductance. 1/R

Resistance of Conductor: p*(l/A)

l=length, A=area. P= constant of material of conductor called specific resistance, Si unit ohm*meter.

Specific Conductance of Conductivity: 1/P and SI unit mho*m^-1

Combination of Resistance: 

Series combination: R=R1+R2+R3...

Parallel Combination R=1/R1+1/R2+1/R..............

Electric Power: The rate at which electric energy consumed in circuit is called electric power=I^2R

1 KWH: 3.6 * 10^6 Joule.

Ammeter: Device used to measure electric current in a circuit. is connected in a series in a circuit.

The resistance of an ideal ammeter is zero.

Voltmeter: Used to measure the potential difference between two point in a circuit. It is connected in parallel to the circuit. The resistance of an ideal volt meter is infinite.

Electric Fuse: -It is a small conducting wire of alloy and copper, tin and lead. Pure fuse is made of Tin.

The fuse material should be of low melting point and high resistance.

Galvanometer: Use to detect and measure small electric current in a circuit. It can measure upto 10^-6 A. It can be converted into ammeter by connecting a shunt parallel to it.

Shunt: Shunt is a wire of very small resistance. converted into voltmeter by connecting a very high resistance in its series.

**Direction of induced current is determined with the help of Fleming's right hand rule of Lenz Law.

Transformer: Convert low voltage Ac into high voltage Ac and high Voltage ac into low Voltage Ac.

Electromagnetic Induction: Whenever there is a change of magnetic flux linked with a circuit, an emf is induced in a circuit. This phenomena is called electromagnetic induction.

Application: A.C Dynamo, Microphone, 

** The current generated in the power station are alternating current having voltage 22000 volt or more