Electricity-Class 10th Science Notes

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Electricity– Class 10th science notes

Introduction

Electricity is a fundamental aspect of our daily lives, powering homes, industries, and electronic devices. It is the flow of electric charge through a conductor, which is essential for operating various appliances. The study of electricity involves understanding electric circuits, resistance, potential difference, and current. The principles of electricity are based on fundamental laws like Ohm’s Law and Joule’s Law. Mastering these concepts helps in understanding modern electrical systems and their applications in real life.

electricity class 10th notes

Key Terms

  1. Electric Current (I) – The flow of electric charge in a conductor per unit time. Measured in Amperes (A).
  2. Potential Difference (V) – The work done to move a unit charge between two points in a circuit. Measured in Volts (V).
  3. Resistance (R) – The opposition offered by a conductor to the flow of current. Measured in Ohms (Ω).
  4. Ohm’s Law – The relationship between voltage, current, and resistance, given by V=IR
  5. Resistivity (ρ) – The property of a material that defines how strongly it resists current flow. Measured in Ωm.
  6. Series Circuit – A circuit where components are connected end-to-end, and the current remains the same throughout.
  7. Parallel Circuit – A circuit where components are connected across the same voltage source, and the total resistance decreases.
  8. Electric Power (P) – The rate of doing electrical work, given by P=VIP = VI. Measured in Watts (W).
  9. Heating Effect of Current – The process in which electrical energy converts into heat, described by Joule’s Law of Heating.
  10. Fuse – A safety device that prevents excess current by melting and breaking the circuit when the current exceeds a safe limit.

Electric Current and Circuit

Electric current is the flow of electric charge through a conductor, such as a wire. It is carried by electrons in a metallic conductor. In a circuit, current flows from the positive terminal of the battery to the negative terminal through conducting wires. A circuit consists of components like a battery, switch, resistors, and appliances. The conventional direction of current is opposite to the actual flow of electrons. The current (I) in a conductor is given by:

I=Q/t

where Q is charge in coulombs and t is time in seconds.

Electric Potential and Potential Difference

Electric potential is the work done in moving a unit charge from one point to another in an electric field. Potential difference (V) is the difference in electric potential between two points in a circuit. It is measured using a voltmeter and given by:

V=W/Q

where W is work done and Q is charge. A higher potential difference means a stronger push for electrons, leading to a greater flow of current.

Ohm’s Law

Ohm’s Law states that the current (I) flowing through a conductor is directly proportional to the voltage (V) across it and inversely proportional to the resistance (R).

V=IR

where:

  • V = Voltage in volts
  • I = Current in amperes
  • R = Resistance in ohms

Example

If a 6V battery is connected to a resistor of 3Ω, the current flowing is:

I=V/R

=6/3

=2A answer

Factors Affecting Resistance:
  • Length of the Conductor (R∝L)
  • Cross-sectional Area (R∝1/A )
  • Material of the Conductor
  • Temperature

Resistance and Resistivity

Resistance is the property of a conductor that opposes the flow of current. It depends on material, length, and cross-sectional area. Resistivity (ρ\rho) is a material property that defines its resistance per unit length and area. The formula is:

R=ρ ( L/A)

where L = length, A = area, and ρ = resistivity (Ωm).

Comparison of Resistivity of Different Materials:

MaterialResistivity (Ωm)
Copper1.68×10^-8
Silver1.59×10^-8
Nichrome1.10×10^-6

Series and Parallel Circuits

Series Circuit:

  • The same current flows through all components.
  • Total resistance: R(total) =R1+R2+R3+…R n
  • Example: Fairy lights are connected in series.

Parallel Circuit:

  • The voltage remains the same across each branch.
  • Total resistance: 1Rtotal=1/R1+1/R2+… 1/R n
  • Example: Household wiring follows a parallel circuit system.

Heating Effect of Electric Current (Joule’s Law of Heating)

When electric current passes through a conductor, heat is generated. The heat produced (HH) is given by:

H = I2Rt

where I = current, R = resistance, t = time.

Applications:
  • Electric Heaters & Irons – Convert electrical energy into heat.
  • Electric Fuse – Prevents overheating by melting.

Electric Power and Energy

Electric power is the rate at which electrical energy is converted into other forms like heat or light. It is given by:

P=VI  = I2R = V2/R

where:

  • P = Power (W)
  • V = Voltage (V)
  • I = Current (A)
  • R = Resistance (Ω)

The SI unit of power is Watt (W), and commercial electrical energy is measured in kilowatt-hour (kWh).

1 kWh = 1000 W × 3600 s = 3.6 × 10⁶ J

Applications of Electricity in Daily Life

  1. Electric Circuits – Used in homes, industries, and transportation.
  2. Electric Heating – Geysers, ovens, and heaters use the heating effect of current.
  3. Electric Transportation – Electric vehicles (EVs) use batteries to power motors.
  4. Safety Devices – Electric fuses and circuit breakers prevent damage due to high current.

Conclusion

Electricity is a crucial part of modern life, enabling communication, transportation, and industry. Understanding its principles helps in efficient and safe usage. Concepts like Ohm’s Law, Resistance, and Joule’s Heating Effect form the foundation of electrical engineering and technological advancements. By studying electricity, we can optimize energy use and develop better electrical systems for a sustainable future.