CBSE CLASS 10th Electricity Notes
Now here in this post, we will discuss the Complete Course detail of 10th Class Electricity Notes. We will start everything from the very basics of this Chapter so-called Electricity. Actually, In the 10th class, We have to study the basics of Electricity. So we will start with the basics of electricity which is Charge.
Definition of Charge
There is no exact definition of charge.so we shall proceed to define charge on the basis of the property of charge. the charge is an internal property of everything which has a tendency to either attract or repel small pieces of the object. The charge represents the internal property of the fundamental particle electron and proton. The charge is Conserved which means Neither charge can be created nor destroyed.
There are two Types of Charge (1.) Positive charge (2) Negative Charge.
Main Property of Charge
- Like charge repel each other
- Unlike Charge Attract each other.
Two different objects which are charged by unlike charge will attract each other. that means force between two differently charged objects has attractive nature. And Just the opposite of it two different objects which are charged by the same charge will repel each other. That means force between the two same charges has repulsive nature.
To find out the Force between two charged objects.JJ Columb has proposed a law which is called Columb's law. Which states that
the force between two charges is (a)directly proportional to the magnitude of the charge
and(b) inversely proportional to the square of the distance between them.
let to charge Q1 and Q2 are placed at a distance of r meters from each other than
according to the Coulomb law
F∝Q1Q2
F∝1/R2
Now from above-given two-equation
F∝(Q1Q2)/R2
F∝(Q1Q2)/R2
F = K(Q1Q2)/R2
Where K is a constant.
Conversely, An object is said to be negatively charged if the number of electrons is greater than the number of protons.
if two objects are positive and Negative Charges respectively as shown below in the figure. Since these charges not transferring on either object hence it is called static charge.
if we connect these charged objects by a conductive wire then we will find that charge starts to flow from the Positive charge object to the negative charge object. Transferring of charge happens due to potential differences.
Where K is a constant.
The flow of Electric Charge
We know that an object is said to be Positively Charged if the number of electrons is less than the number of protons on that object.Conversely, An object is said to be negatively charged if the number of electrons is greater than the number of protons.
if two objects are positive and Negative Charges respectively as shown below in the figure. Since these charges not transferring on either object hence it is called static charge.
if we connect these charged objects by a conductive wire then we will find that charge starts to flow from the Positive charge object to the negative charge object. Transferring of charge happens due to potential differences.
What is Electric Potential? Definition of Electric Potential
Work done on a unit positive charge by bringing it from infinity to a point in an electric field is called electric potential at that point. it is a physical quantity and measured in (Joule/coulomb) which is called Volt. it is a scalar quantity.
Let W be the amount of work done while bringing Q coulomb of charge in an electric field then electric potential (V) is given as
V = W/Q (Volt)
Potential Difference
Potential Difference between two-different point Potential is called the electric potential difference. Let the Potential of two different points is V1 and V2 then the Potential difference is Represented as ΔV and is given as
ΔV = V2 -V1
Electric Current
The rate of flow of charge through a given cross-sectional area of a conductor is called electric current. It is a physical quantity and measure in Coulomb/second which is called Ampere and represented by A.
The flow of charge happened due to potential differences. if there is no potential difference, then there is no flow of charge hence there is no flow of electric current.
if Q coulomb of charge flow in t second of time then electric current can be calculated as
I = Q/t (coulomb/second)
Coulomb/second is called Ampere.
Electric Circuit
When an electric component like an electric bulb, fan, TV, etc is connected by a wire with an electrical energy source(Battery, Cell, Generator) and makes a completely closed path is called an electric circuit.As shown in the figure below
Ammeter
An ammeter is an electrical instrument that is used to measure the amount of electric current flowing through a closed circuit. An ammeter is connected in series with the electric circuit. As shown in the figure.
Voltmeter
it is an electrical instrument that is used to measure the potential difference between two points of the electric circuit. A voltmeter is always connected in parallel with the electric circuit. As shown in the figure.
Difference Between AC and DC
If the current flowing through an electric circuit is constant and unidirectional with respect to time then it is called direct current (DC).
if the current flowing through an electric circuit is varying with respect to time then it is called Alternating Current(AC).
OHM's Law
ohm's law state that the Current flowing through a given conductor is proportional to the potential difference between the terminal of the conductor.
Let V be the Potential difference between the terminal of the Conductor and I is the current flowing through it then According to ohm's law
I ∝ V
V∝ I
V = IR
Where R is Constant and called the Resistance of the Current-Carrying conductor.
Ohm's Law on Graph
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| Ohm's Law |
What is Resistance?
Resistance is an internal property of any material which opposes the flow of electric current through it. it is a physical quantity that is measured in ohms and denoted by omega (Ω). Material that offers Resistance is called Resistor.
What is Resistivity?
The resistivity of any material is an inherent property of the material that tells that up to what extent a particular material can offer resistance or up to what extent, it can oppose the flow of electric current. it is also a physical quantity and measured in ohm-meter and denoted as (Ω-m)
Factor On which Resistance of Conductor depend
The resistance of any conducting material is a function of the type of material and its dimension. Hence these parameters affect the Resistance value of the Resistor. The resistance of any conductor depends on
Resistance is proportional to the length of the Conductor
i.e R ∝ l ---(1)
Resistance inversely proportional to the cross-sectional area of the Conductor
i.e R ∝ 1/A---(2)
On Combining the above two equation
R ∝ l/A
R = ρ(l/A)
here ρ is the proportionality Constant called the Resistivity of the material or Specific Resistance of the Material.
Combination of Resistor
Resistors are components that offer resistance. Resistors are represented in electronics or electric circuits shown below. To get a higher value of resistance combination of the resistor is adopted. there are two types of the main combination of the resistor are adopted which are:-
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| Resistor symbol |
(a) Series Combination of Resistor
if two or more than two Resistor is connected to each other end by end in such a way that after connection two end are left then this type of combination of resistors are called a series Combination of the resistor. The Series Combination of the resistor is shown below in the circuit.
here four resistors are connected in series. The Equivalent Resistance of this combination of the resistor is
Req =R1+R2+R3+R4
(b) Parallel Combination of Resistor
If the terminal of two or more than two resistors is connected together then this type of combination of resistors is called parallel Combination of the resistor.
Parallel Combination of Resistors are shown below:-
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| Parallel Combination |
in the above-given figure, four resistors are combined in parallel connection. The Equivalent Resistance between the Terminal of the Circuit is calculated as
Heating effect of electric current
when a potential difference applied across the terminal of the conductor then free electrons of the conductor gain energy and starts to move from low potential to high potential and collide with the atom of the Conductor and release its energy to the colliding atom,
this process continued till the potential is applied across the terminal of the conductor. Due to Transferring energy temperature of the Conductor increases and it becomes hot. this effect is called the heating effect of the electric current.
From the definition of Electric Potential, if the potential difference between two terminal of a conductor is V then Work done by bringing Q coulomb of charge is given as
W = V x Q Joule
W = IR x Q (from ohm's law)
W =IR x It (I =Q/t)
W =I2RT
Joule's law of Heating
First time Joule has establish a relation between heat and electric current. This relation is called Joule's law of heating. According to this law if there is a current flowing through a resistor the amount of heat energy(Q) evolved is
(a).proportional to the square of the electric current flowing through that resistor
Q ∝ I2
(b) proportional to the Resistance of the resistor
Q ∝ R
(c) proportional to the current flowing time through the Resistor
Q ∝ R
Electric Power
Electric Energy Consumed by an electrical instrument in one second is called the electric power of the instrument. it is denoted by the capital letter P. it is a physical quantity and is measured in watts.if W is the amount of work done by an electric instrument in t second then the electric power of the instrument is
P = W/t
P = I2Rt/t
P =I2R
As we all know that
W = VxQ
W = VxIt
W =VIt
P =VIt/t
P = VI
W=VIt=Vx(V/R)t
W =V2t/R
P = W/t
P = V2/R
