📘Class 10 Science – Chapter: Sources of Energy Notes

☀️ Introduction to Energy Sources

  • Energy is the capacity to do work.

  • All living and industrial processes need energy.

  • Sources of energy are classified based on availability, renewability, and traditional use.

⚡️ Classification of Sources of Energy

Category Type Example
Renewable Can be replenished Solar, Wind, Hydro, Biomass
Non-renewable Limited, exhaustible Coal, Petroleum, Natural Gas

🔥 Conventional Sources of Energy

1. Fossil Fuels

  • Formed by decomposition of biomass under pressure and heat.

  • Include coal, petroleum, natural gas.

Disadvantages:

  • Air pollution (CO2, SO2)

  • Non-renewable

  • Causes global warming

Example Equation (in simple font):
Carbon + Oxygen → Carbon dioxide + Heat

2. Thermal Power Plant

  • Uses heat from burning coal to generate steam which rotates turbines.

  • Located near coal/oil fields to reduce transport cost.

3. Hydroelectric Power Plant

  • Uses kinetic energy of flowing water to rotate turbines.

  • Built on dams across rivers.

Pros:

  • Renewable, clean

Cons:

  • Large land submergence

  • Affects local habitats

☔️ Non-conventional Sources of Energy

1. Solar Energy

  • Energy from the Sun.

  • Captured using solar panels and solar cookers.

Working of Solar Cooker:

  • Black surface absorbs heat

  • Glass traps infrared radiation (greenhouse effect)

2. Wind Energy

  • Wind turns turbine blades to produce electricity.

  • Requires wind speeds >15 km/h.

Limitations:

  • Need large land area

  • Noise pollution

3. Biomass Energy

  • Energy from organic matter (cow dung, plant waste).

  • Biogas plant used for gas production.

Reaction in Biogas Plant:
Organic matter → CH4 + CO2 + H2 + H2S

4. Tidal and Wave Energy

  • Generated by the movement of ocean water.

  • Tidal barrage or wave turbines used.

5. Geothermal Energy

  • Heat from Earth’s interior.

  • Steam is used to turn turbines.

6. Nuclear Energy

  • Energy from fission of heavy nuclei like uranium-235.

Example Equation:
U-235 → Ba-139 + Kr-94 + 3n + energy

Advantages:

  • Huge energy output

  • Low fuel requirement

Disadvantages:

  • Expensive

  • Radioactive waste

📊 Comparison Table of Energy Sources

Source Renewable Pollution Cost Efficiency Reliability
Solar Yes No High setup Medium Weather dependent
Wind Yes No High setup Medium Irregular
Biomass Yes Low Low Low Medium
Fossil Fuels No High Low High Reliable
Nuclear No Low (CO2) Very high Very high High

🔢 Criteria for Ideal Source of Energy

  • Easily available

  • Does not cause pollution

  • High calorific value

  • Economical and efficient

  • Easy to transport and store

Hand written Notes Of CELL: The Fundamental unit of Life