2.  Electrical Energy If man A pushed 10 boxes 1 meter in one hour and man B pushed 1 box 1 meter in one hour, which man expended the greatest amount of energy in one hour? Man A

3. If battery A pushed 10 electrons 1 m in 1 second with a force of 1.5 volts and battery B pushed 1 electron 1m in 1 second with the same force of 1.5 volts, which battery exerted more energy in 1 second? Battery A

4.  Energy  Is defined as the ability to do work  Electrical Energy  The energy transferred to the load by moving charges

5. Electrical Energy = voltage drop x electrical current x time interval E = V x I x ∆t Where: ‘E’ is the electrical energy measured in Joules (J) ‘V’ is the voltage drop measured in volts (V) ‘I’ is the electric current measured in amps (A) ‘∆t’ is the time interval in seconds (s) (DO NOT WRITE)The Joule is the SI unit for energy and is what is known as a derived unit which means you must remember it’s definition.

7.  Example(Take notes):  How much energy is released from a 1.5 volt battery passing electrons into a circuit at a rate of 0.5 amps for a period of 5 seconds? V = 1.5 VI = 0.5 A∆t = 5 s E= (1.5 V)x(0.5 A)x(5 s) = 3.75 J The unit for energy released is Joules only if the time interval is in seconds

8.  One Joule is a small amount of energy. In fact it can only light a 100W bulb for 1 second.  The Joule was too small for everyday use so the Watt hour (Wh) was adopted  (1Wh = 3600J)  Example: How much energy was released from a 6volt battery in a flashlight that was switched on for 3 hours and the current flowing through the bulb was 0.35 A.  V = 6VI = 0.35A∆t = 3h  E = V x I x ∆t  E = (6V)x(0.35A)x(3h)  E = 6.3 Wh

9.  REMEMBER!!!!  ∆t in seconds → Joules(J)  ∆t in hours → Watt hours (Wh)