NCERT Solutions Class 10th Science Chapter

Textbook	NCERT
Class	10^th
Subject	Science
Chapter	11^th
Chapter Name	Electricity
Category	Class 10th Science
Medium	English
Source	Last Doubt

NCERT Solutions Class 10th Science Chapter – 11 Electricity Notes What is electricity short notes, What is the SI unit of electricity What are the two types of circuit discuss Electricity Notes.

Electric Current

SI unit – Ampere

What is it – It is the rate of flow of electric charges (electrons) in a conductor.

Experimentaly
Measured by an ammeter

How is it connected – always in series in a circuit through which we measure current

What is a circuit – Electric circuit is a continuous and closed path of an electric current.

Direction of current flow in circuit – Positive terminal of the cell to the negative terminal
It is the rate of flow of electric charges (electrons) in a conductor.

Mathematically
I = Q/t

Where
Q is the net charge that flows across cross-section of a conductor in time.

Charge is a fundamental particle in an atom. It may be positive or negative.

Like charges repel each other.

Unlike charges attract each other.

Coulomb (C) – S. I. unit of charge

1 coulomb charge = Charge present on approx. 6 × 10¹⁸ electrons

Charge on 1 electron = Negative charge of 1.6 × 10^-19 C . Q = ne

Where Q = Charge (total)
n = No. of electrons
e = Charge on 1 electron

Current (I) – The rate of flow of charge is called current.

Charge = Current/Time
I = _Q_

S. I. unit of current = Ampere (A)^t
1 A = 1 Cs-¹
1 mA = 10^-3 A
1 μA = 10^{-6 A}

Current is measured by Ammeter. Its symbol is
b 2

Ammeter has low resistance and always connected in series.

Direction of current is taken opposite to flow of electrons as electrons were not known at the time when the phenomenon of electricity was discovered first and current was considered to be flow of positive charge.

Potential Difference (V) – Work done to move a unit charge from one point to another.

V = w/Q

S. I. unit of Potential difference = Volt (V) 1 V = 1 JC^-1

1 Volt – When 1 joule work is done in carrying one coulomb charge then potential difference is called 1 volt.

Voltmeter – Instrument to measure potential difference.

• It has high resistance and always connected in parallel. Symbol is V.
• Cell is the simplest device to maintain potential difference.
• Current always flow from higher potential to lower potential.

Symbols of Some Commonly Used Components in Circuit

Electric Cell
Battery
Key (Open)
Key (Closed)
Wire Crossing (Without Join)
Wire joint
Electric bulb
Resistance
Rheostat
Ammeter
Voltmeter

Ohm’s Law – Potential difference across the two points of a metallic conductor is directly proportional to current passing through the circuit provided that temperature remains constant.

Mathematical expression for Ohm’s law
V ∝ I
V = IR
R is a constant called resistance for a given metal.
V-I graph for Ohm’s law

Screenshot 20230203 233559

Resistance (R) –

It is the property of a conductor to resist the flow of charges through it.
Ohm (Ω) S. I. unit of resistance.
1 ohm = 1 Volt/1 ampere

Rheostat – Variable resistance is a component used to regulate current without changing the source of voltage.

Factors on which the Resistance of a Conductor depends – Resistance of a uniform metallic conductor is directly proportional to the length of conductor, inversely proportional to the area of cross-section, directly proportional to the temperature and depend on nature of material.

Resistivity (P) – It is defined as the resistance offered by a cube of a material of side 1 m when current flows perpendicular to its opposite faces.

• Its S.I. unit is ohm-metre (Ωm).
• Resistivity does not change with change in length or area of cross-section but it changes with change in temperature.
• Range of resistivity of metals and alloys is 10^-8 to 10^-6 Ωm.
• Range of resistivity of insulators is 10¹² to 10¹⁷ Ωm.
• Resistivity of alloy is generally higher than that of its constituent metals.
• Alloys do not oxidize (burn) readily at high temperature, so they are commonly used in electrical heating devices.
• Copper and Aluminium are used for electrical transmission lines as they have low resistivity.

Resistors in series
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When two or more resistors are connected end to end, the arrangement is called series combination.

• Total/resultant/overall/effective resistance in series
R_s = R₁+ R₂ + R₃
• Current through each resistor is same.
• Equivalent resistance is larger than the largest individual resistance.
• Total voltage Sum of voltage drops
V = V₁ + V₂ + V₂
• Voltage across each resistor:

V₁ = IR₁
V₂ = IR₂
V₃ = IR₃
V = IR₁ + IR₂+ IR₃
IR = I(R₁ + R₂+ R₃)
R = R₁ + R₂+ R₃
[V₁ + V₂ + V₁ = V]
V = IR

Resistors in Parallel
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Voltage across each resistor is same and equal to the applied voltage.

Total current is equal to sum of currents through the individual resistance.

I = I₁+ I₂+ I₃
V/R = V/R₁+ V/R₂+ V/R₃

Reciprocal of equivalent resistance is equal to sum of reciprocals of individual resistances.

1/R_p= 1/R₁+ 1/R₂+ 1/R₃

Equivalent resistance is less than the value of the smallest individual resistance in the combination.

Advantages of Parallel Combination over Series Combination

(i) In series circuit, when one component fails, the circuit is broken and none of the component works.

(ii) Different appliances have different requirement of current. This cannot be satisfied in series as current remains same.

(iii) The total resistance in a parallel circuit is decreased.

Heating Effect of Electric Circuit – If an electric circuit is purely resistive, the source of energy continually get dissipated entirely in form of heat. This is known as heating effect of electric current.

As, E = P×T ⇒ t VI {E = H}
Heat produced, H = VI t {V = IR}
Or, Heat produced, H = I²Rt

Joule’s Law of Heating Effect of Electric Current – It states that the heat produced in a resistor is

(i) directly proportional to square of current, H∝ l²
(ii) directly proportional to resistance for a given current, H∝ R
(iii) directly proportional to time for which current flows through the conductor, H∝ t.

So, H = I²Rt

• Heating effect is desirable in devices like electric heater, electric iron, electric bulb, electric fuse, etc.

• Heating effect is undesirable in devices like computers, computer monitors (CRT), TV, refrigerators etc.

• In electric bulb, most of the power consumed by the filament appears a heat and a small part of it is radiated in form of light.

• Filament of electric bulb is made up of tungsten as
(i) it does not oxidize readily at high temperature.
(ii) it has high melting point (3380° C).

• The bulbs are filled with chemically inactive gases like nitrogen and argon to prolong the life of filament.

Electric Fuse –

• It is a safety device that protects our electrical appliances in case of short circuit or overloading.

• Fuse is made up of pure tin or alloy of copper and tin.

• Fuse is always connected in series with live wire.Fuse has low melting point.

• Current capacity of fuse is slightly higher than that of the appliance.

Electric Power – The rate at which electric energy is consumed or dissipated in an electric circuit.

P = VI
P = I²R = V²/R

S.I. unit of power = Watt (W)

1 Watt = 1 volt × 1 ampere

⇒ Commerciat unit of electric energy = Kilo watt hour (KWh)

1 KWh = 3.6× 10⁶ j
1 KWh = 1 unit of electric energy

NCERT Solution Class 10th Science All Chapters Notes

Chapter 1 – Chemical Reactions and Equations

Chapter 2 – Acids, Bases, and Salts

Chapter 3 – Metals and Non-Metals

Chapter 4 – Carbon and Its Compounds

Chapter 5 – Life Processes

Chapter 6 – Control and Coordination

Chapter 7 – How Do Organisms Reproduce

Chapter 8 – Heredity

Chapter 9 – Light reflection and refraction

Chapter 10 – Human eye and colorful world

Chapter 11 – Electricity