• Heat

   

-         Energy transferred from one body to another

-         Result of temp. difference

-         Unit: J (joule)

• Internal energy 

   

• Energy stored in a body

   

• internal energy ↑

   

• Temp. ↑

   

• Particles move faster and faster

   

• Average kinetic energy ↑

   

• Change of states (Solid → Liquid / Liquid→ Gas ONLY)

   

• Particles become further apart

   

• Potential energy ↑

   

• Unit: J

   

• = Potential energy + kinetic energy

   

** 1kJ = 10^3 J,   1MJ = 10^6 J

• Power

   

-         P = E/t   (E= Pt)

§ P= Power

§ E= energy

§ T= time

-         Unit: W (Watt)

** 1W = 1Js^-1        ← Time unit 一定要轉做Second (秒)

    1kW = 10^3 W,   1MW = 10^6 W

     1kW h = 3.6 MJ

• Measurement

   

-         Joulemeter

§ Measure Low voltage (12 V a.c.)

-         Kilowatt ~ hour meter

§ Measure Mains supply (220 V a.c.)