2. There are two requirements that must be met in order to establish an electric circuit 1.There must be an energy source (battery) capable of doing work on charge to move it from a low energy location to a high energy location. This establishes a potential between the two ends of an electric circuit. 2.There must be a closed conducting loop that connects from the high potential to the low potential.

3.  The flow of electric current is dependent on a difference of potential between two points  If there is no difference, there is no flow  Current is the rate at which a charge flows past a point on a circuit  Current flows from the negative terminal to the positive terminal

4. 

5.  The current in a light bulb is 0.835 A. How long does it take for a total charge of 1.67 C to pass a point in the wire?

6.  A hair dryer draws a current of 9.1 A. How long does it take for 1.9x10 3 C of charge to pass through the hair dryer?

7.  Light a bulb, spin a motor, listen to music  Considered a load  The rate at which energy is consumed (used) by a load is called power  Recall from last semester that power is a rate of doing work  Similarly, electrons are now doing work  Electric power is the rate at which energy is consumed

8. 

9. 

10.  A 6.0 V battery delivers a 0.50 A current to an electric motor connected across its terminals. If the motor runs for 5.0 minutes, how much electric energy is delivered?

11.  Power companies actually sell energy  A kilowatt is equal to 1000 W  Power companies sell energy in large quantities called the kilowatt hour  A kilowatt hour is equal to 1000 W delivered over 3600 s (1 hour) or 3.6 x 10 6 J

12. To calculate cost: 1. Determine the power in kilowatts 2. Determine energy consumed by multiplying power in kilowatts by time in hours 3. Multiply the kilowatt hour by the cost for each kilowatt hour

13.  A 60 W light bulb is connected to a 120 V power source. The power company charges $0.11 per kWh. ◦ What is the current through the light bulb? ◦ How much would it cost to keep the bulb lit for two hours?