Define sources of energy

Energy is the capacity of a body to do work.
We Classify the sources of energy on the basis of:
<u>Occurence:</u>
- Natural Sources: Natural energy sources are those which are made available to us by nature. Solar energy, wind energy, energy from water (hydro energy) are some of such natural sources of Energy.
- Synthetic Sources: Synthetic energy are those that use man-made materials as sources of energy. Fir example, chemical energy, stored in the batteries, (used in calculators, watches, etc.) is a synthetic source of energy.
<u>Physical</u><u> </u><u>State:</u>
- Solid: Firewood, Charcoal, coal are examples of solid fuels.
- Liquid: Kerosene, Petrol & diesel are all liquid fuels.
- Gas: Petroleum gas, commonly used as LPG (Liquified Petroleum Gas), & natural gas, also used CNG (Compressed Natural Gas), are examples of gaseous fuels
<u>Availability</u><u>:</u>
- Renewable: A renewable source of energy is a natural resource that can replenish itself naturally over a short period of time. Wind, sun, biomass (from plants) & hydropower (from water) are all renewable sources of energy. These arr inexhaustible natural resources.
- Non-renewable: Energy sources which get us & cannot be replaced or replenished in a short period of time are called non-renewable sources of energy. These are also called exhaustible natural resources. Fossil fuels, (like petroleum, natural gas & coal), are non-renewable sources of energy.
<h2>Hope It's Helped! :D</h2>
Electricity<span> is </span>measured<span> in </span>units<span> of power called Watts</span>
Answer:
All of the above
Explanation:
Astronomers use all of those measures to classify stars. If you want to look more into classifying stars, check out the Hertzsprung-Russel Diagram. It covers how to identify red giants, main sequence, dwarf stars, ect. Distance from earth is typically measured in light years. The color of stars generally determines how hot they are. (Blue stars are the hottest) Also, the parallax method is used to measure stars that are closer to earth. This method relies heavily on geometry though.
Hope this helped!