This is a ppt which is based on electricity chapter of class 10 in science ncert cbse book . it will definitely enhance your knowledge and clear all concepts about this chapter .
2. CONTENT
๏ง INTRODUTION
๏ง ELECTRIC CHARGE AND ITS PROPERTIES
๏ง CONDUCTORS AND INSULATORS
๏ง ELECTRIC CURRNT
๏ง POTENTIAL DIFFERENCE
๏ง OHMโS LAW
๏ง RESISTANCE IN SERIES AND PARALLEL
๏ง HEATING EFFECT OF ELECTRICITY AND ITS APPLICATION
3. INTRODUCTION
Electricity is probably the eighth wonder of the modern civilized
world . Its discovery and utility have revolutionized the
industries and home of the civilized world . Life today is totally
dependent on it .
Electricity is one of the form of energy and it can be produced
from other types of energy . Its great advantages over all other
type of energy are it :
1. Cleanness
2. Flexibility
3. Efficiency
4. Easier Transmission
4. ELECTRIC CHARGE AND ITS PROPERTIES
โข Charges โ Property of an object by virtue object which it
applies force on another objet is called charge .
The S.I. unit of charge is coulomb. An electron posses a negative
charge of 1.6 ร 10โ19
.
โข Properties
1. Unlike charges attract each other and like charges repel each
other .
2. Electric charge is conserved .
3. Electric charge is additive .
4. The forces between two charges varies directly as the
product of two charges and inversely as the square of the
distance between them .
๐น = ๐
๐1 ๐2
๐2
5. CONDUCTORS AND INSULATORS
Conductors -These substance have the property to conduct electricity
through them. These have free or loosely held electrons which helps in
conducting electricity. Example โ copper.
Insulators -These substance have the property to obstruct the flow of
electricity. These do not have free electrons present in them. Example โ
Rubber Insulation.
6. ELECTRIC CURRNT
โข Electric current โ it is defined as the rate of flow of electric
charges .
S.I.Unit โ Ampere .
Formulae - ๐ผ =
๐
๐
or ๐ = ๐ผ๐
โข 1 ampere โ current flowing through a conductor is said to 1
ampere if one coulomb of charge flows through it in one
second .
1 ๐๐๐๐๐๐ =
1 ๐๐๐๐๐ข๐๐
1 ๐ ๐๐.
7. POTENTIAL DIFFERENCE
Potential difference :- between two points A and B of a conductor is the
amount of work done to move a unit charge from A to B.
๐๐๐ก๐๐๐ก๐๐๐ ๐๐๐๐๐๐๐๐๐๐ =
๐๐๐๐ ๐ท๐๐๐
๐โ๐๐๐๐
The SI unit of potential difference is volt (V).
One volt is the potential difference when 1 joule of work is done to move a
charge of 1 coulomb from one point to the other.
8. OHMโS LAW
โข Ohms law is a relationship between the potential
difference across a conductor and the current flowing
through it.
โข Ohmโs law states that :-
โThe current flowing through a conductor is directly
proportional to the potential difference between its ends
provided its temperature remains constantโ
๐ผ โ ๐ or R =
๐
๐ผ
Where R is a constant called resistance for a given metallic
wire at a given temperature.
9. RESISTANCE IN SERIES
When three resistors R1, R2 and R3 are connected in series
across AB
โข i) The current in all the resistors is the same.
โข ii) The total voltage (PD) across the resistors is equal to the
sum of the voltage across each resistor.
V = V1 + V2 + V3
โข iii) The equivalent resistance is the sum of the resistances of
each resistor.
RS = R1 + R2 + R3
10.
11. RESISTANCE IN PARALLEL
โข When three resistors R1, R2 and R3 are connected in
parallel across AB,
i) The voltage (PD) in all the resistors is the same.
ii) The total current in all the resistors is the sum of the
current in each resistor.
I = I1 + I2 + I3
iii) The reciprocal of the equivalent resistance is the sum of
the reciprocals of each resistance.
12.
13. HEATING EFFECT OF ELECTRICITY AND ITS APPLICATION
Jouleโs law of heating Let An electric current I is flowing
through a resistor having resistance equal to R. The
potential difference through the resistor is equal to V. The
charge Q flows through the circuit for the time t. Thus, work
done in moving of charge Q of potential difference V = VQ
Since, this charge Q flows through the circuit for time t.
The heat produced in wire is directly proportional to i.
Square of current. ii. Resistance of wire. iii. Time for which
current is passed.
๐ป = ๐ผ2 ๐ ๐
14. Applications of heating effect of electric current
There are many practical uses of heating effect of
current. Some of the most common are as follows.
โข An incandescent light bulb glows when the filament is
heated by heating effect of current, so hot that it glows
white with thermal radiation (also called blackbody
radiation).
โข Electric stoves and other electric heaters usually work
by heating effect of current. โข
โข Soldering irons and cartridge heaters are very often
heated by heating effect of current.
โข Electric fuses rely on the fact that if enough current
flows, enough heat will be generated to melt the fuse
wire.
16. โข Electronic cigarettes usually work by heating effect of
current, vaporizing propylene glycol and vegetable glycerin.
โข Thermistors and resistance thermometers are resistors
whose resistance changes when the temperature changes.
These are sometimes used in conjunction with heating effect
of current(also called self-heating in this context): If a large
current is running through the nonlinear resistor, the
resistor's temperature rises and therefore its resistance
changes. Therefore, these components can be used in a
circuit-protection role similar to fuses, or for feedback in
circuits, or for many other purposes. In general, self-heating
can turn a resistor into a nonlinear and hysteretic circuit
element