Electrical Power and Energy

When a battery sends a current through a resistor, as in Fig. the battery is furnishing energy to resistor. In effect, the battery lifts charge from the low potential at b to higher potential at a. the potential difference between these two points is simply the voltage of the battery. The work done by the battery in the process of lifting a charge q from b to a is, Let us next compute the power output of the battery as it drives a current rough the circuit. We have known at 8 th grade that Power = W (P) t P = V I By using Ohm’s Law (V = IR) Prove that can express with P = IRI = I 2 R P = watt (J/s) V = volt R = ohm W = Joule t = second Q =coulomb

Factor that can influence the magnitude the power Voltage, Resistance, Current, Time, charge Power in electrical devices

How to calculate Energy? R Voltage resource o I Electrical Energy’s signed by E The unit (SI) is watt seconds E = P t E= V.I.tE = I 2 Rt (Because V = IR)

KWh meter, use to measure electrical Energy

Electric Stealing CALCULATE ELECTRIC COST Cost = Energy x tariff rate = KWh x tariff rate (in Rupiah)

Exercises 1.In a house, there are 5 lamps of 60 watt each, a TV of 70 watt. If those electric devises are Turned on for 4 hours every day, what is the cost that must be paid for 1 month (30 days) If price of 1 kWh = Rp A TV turned on for 10 hours per day, is connected to a voltage of 220 V and needs current Of 3 A. If the price of 1 kWh = Rp , calculate the electricity cost that must be paid for 1 month ( 30 day)