2. ENERGYENERGY
ENERGYENERGY
Energy is the capacity to do workEnergy is the capacity to do work
The SI unit of energy is Joule (J)The SI unit of energy is Joule (J)
Larger unit of energy are watt- hour andLarger unit of energy are watt- hour and
kilowatt- hour.kilowatt- hour.
1 watt hour = 3600J1 watt hour = 3600J
1 kilowatt hour =3.6×101 kilowatt hour =3.6×1066
JJ
3. Different forms of energyDifferent forms of energy
Mechanical energyMechanical energy
Chemical energyChemical energy
Heat energyHeat energy
Light energyLight energy
Magnetic energyMagnetic energy
Sound energySound energy
4. Transformation of energy.Transformation of energy.
In an electric bulb,In an electric bulb,
Electric energy Heat energy+ light energyElectric energy Heat energy+ light energy
In a microphone,In a microphone,
sound energy electrical energy.sound energy electrical energy.
5. In a loudspeakerIn a loudspeaker
Electrical energy Sound energy.Electrical energy Sound energy.
In an electric bellIn an electric bell
Electrical energy Sound energy.Electrical energy Sound energy.
In an electric motor or fan,In an electric motor or fan,
Electrical energy MechanicalElectrical energy Mechanical
energy.energy.
6. Law of conservation ofLaw of conservation of
energy.energy.
‘‘Energy can neither be created norEnergy can neither be created nor
destroyed. But one form of energy candestroyed. But one form of energy can
be transformed to another form withoutbe transformed to another form without
gain or loss’.gain or loss’.
7. Law of conservation ofLaw of conservation of
energy.energy.
‘‘Energy can neither be created norEnergy can neither be created nor
destroyed. But one form of energy candestroyed. But one form of energy can
be transformed to another form withoutbe transformed to another form without
gain or loss’.gain or loss’.
