The document explains the basics of electric current, charge flow, resistance, and household electrical safety. It details how current is generated by a potential difference, measures resistance in ohms, and highlights the importance of safety devices like fuses and circuit breakers in home wiring. Additionally, it covers various methods through which static electricity can be generated and the principles outlined by Ohm's law.

2. Flow of current
 A charge flows when there is a potential difference
 -- When the ends of an electric conductor are at
different electric potentials, charge flows from one
end to the other
 -- The flow of charge will continue until both ends
reach a common potential
 -- Ex: Difference in water level

3. Electric Current
 Electric Current: The flow of electric charge
-- Solid conductors the electrons can move
around freely carrying the charge
 Electric Current is measured in amperes (A)
amp = 1 coulomb of charge per second
1 coulomb = 6.24 billion electrons

4. Electric Current Cont……
 A current carrying wire does not have a net
electric charge
 While the current is flowing, negative electrons
swarm through the atomic network
 The number of electrons in the wire is equal to the
number of protons
 The number entering is the same as the number
leaving
 The net charge is zero

5. Static Electricity
 Objects can acquire a static electric charge through:
1) Friction (when an object whose electrons are
loosely held rubs against another object)
2) Conduction (when an object with an excess of
electrons touches a neutral object)
3) Induction (a neutral object acquires a charge from
a charged object close by without contact being
made)

6. Resistance
 Resistance: the tendency for a material to
oppose the flow of electrons
 Changes electrical energy into thermal
energy and light
 Ex: lightbulb filament
 Resistance is measured in Ohms (Ω)

7. Conduction
Charging by contact!

8. IV. Control the Flow
 A voltage difference causes the charges to flow
 Flow of charges= current (Amps or A)
 Electrical resistance restricts the movement of
charges
Resistance = current
Pressure = current
(Voltage Difference)

9. Voltage Sources
 Voltage Source: Something that provides a
potential difference
 Dry Cells, Wet Cells and Generators supply energy
that allows charges to move
-- Dry |Wet Cells: Chemical energy converted to
electrical energy
-- Generators: Mechanical energy to electrical
energy

10. Series Circuit
 Current is the same at each point in the circuit
 When another resistor (light bulb) is added in series,
the total resistance increases.
 When resistance increases, current will decrease.
 Decreased current means dimmer light.

11. Electric Resistance
 The amount of charge that flows depends on the
voltage provided by the voltage source
 Electric Resistance: The resistance of a material
to flow of electric current through it: measured in
ohms
-- Depends on the resistance the conductor
provides

12. Electric Resistance
 Thick wires have less resistance than thin wires
 Electric resistance also depends on temperature
-- The greater the jostling about of atoms within
the conductor, the greater resistance the
conductor offers to the flow of charge

13. Ohm`s Law
 Electric Resistance is measured in units called
ohm`s law
Resistance = voltage
Current
Current = voltage
resistance

14. What is the resistance of an electric
frying pan that draws 10 amperes of
current when connected to a 120-
volt circuit?
Resistance = voltage
current
* Measured in ohms

15. Household Electrical Safety
 In a house, many appliances draw current from the same
circuit
 If more appliances are connected to a circuit, more current
will flow through the wires
 More current in wires = more heating in the wires
 More heat causes insulation on wires to melt, which
increases chances of fire
 To protect a house from this, all household circuits have
a:
1. Fuse, or
2. Circuit breaker

16. How much current is drawn by a
lamp that has a resistance of 110
ohms when a voltage of 60 volts is
pressed across it?
Current = voltage
resistance
* Measured in amperes

17. Made By : Sudhanshu
Class : Xth
Roll.No. : 17