Chapter 3: Different Forms of Energy Flashcards
(21 cards)
What is energy?
The ability to do work or cause movement.
What is the unit of energy?
Joules (J)
What does the Law of Conservation of Energy state?
Energy cannot be created or destroyed—it can only be transformed or transferred.
What is thermal energy?
Energy from the random motion of particles (heat).
What is electrical energy?
Energy from the movement of electrons.
What is chemical energy?
Energy stored in molecular bonds.
What is mechanical energy?
Energy from the movement of machines.
What is radiation energy?
Energy carried by electromagnetic waves (ex: light, microwaves).
What is nuclear energy?
Energy stored in the nucleus of an atom, released during fission or fusion.
What is elastic energy?
Energy stored due to compression or stretching (like a spring or elastic band).
What is sound energy?
Energy carried by sound waves (vibrations in air).
What is wind energy?
Mechanical energy generated by moving air.
What is hydraulic energy?
Energy from moving water (rivers, waterfalls).
What is the difference between energy transformation and energy transfer?
Transformation = energy changes form.
Transfer = energy moves from one object/place to another.
What’s an example of an energy transformation in a light bulb?
Electrical energy → light + thermal energy
What’s an example of energy transfer in a kettle?
Heat moving from the coil to the water.
What is energy efficiency?
A measure of how much energy is converted into useful energy.
What is the formula for energy efficiency?
Efficiency (%) = (Useful energy / Total energy consumed) × 100
MATH Q: A light bulb consumes 30 J of energy and produces 20 J of light. What is the efficiency?
(20 ÷ 30) × 100 = 66.7%
MATH Q: A kettle uses 15,500 J and is 85% efficient. How much useful energy does it produce?
15,500 × 0.85 = 13,175 J
MATH Q: A furnace releases 38,000 kJ, loses 7,600 kJ in exhaust and 1,900 kJ in pipes. What’s the efficiency?
Total loss = 9,500 → Useful = 28,500
(28,500 ÷ 38,000) × 100 = 75% efficiency
