Practice Test

1. A sweater will end up with a negative charge when it:


a) Loses Electrons

b) Loses Protons

c) Gains Electrons

d) Gains Protons

e) Loses Neutrons


Answer: C


2. A neutral object is touched with a positivly charged rod. The object will become.


a) Uncharged

b) Grounded

c) Negatively Charged

d) Positive Charged

e) Magnetic


Answer: D


3. In what type of circuit do electrons follow one path from the source to a load, and back to the source?


a) Short Circuit

b) Open Circuit

c) Parallel Circuit

d) Series Circuit

e) Connected Circuit


Answer: D


4. The SI unit for peasuring potential difference is the:


a) Coloumb

b) Ampere

c) Volt

d) Joule

e) Watt


Answer: C


5. Which device would most likely be classified as a load in an electrical circuit?


a) Battery

b) Light Bulb

c) Ammeter

d) Cell

e) None of the Above


Answer: B


6. If V1 = 100V, Vt= 40V and It= 10A. What does V2 and V3 equal if they are connected in parallels to the circuit. (Note, V1 is connected in series)


a) 40 V

b) 30 V

c) 20 V

d) 15 V

e) 10 V


Answer: B


7. A 30 ohms resistor is connected in series to a 10 ohms resistor, and a 120 V supply. The current through the 30 ohm resistor will be:


a) 3 A

b) 4 A

c) 12 A

d) 15 A

e) 0.33 A


Answer: A


8. A toaster uses a current of 550 mA when it is plugged into the wall volatge of 110 V.


a) What is the resistance of the toaster?


I= 550 mA OR 0.55 A

V = 110 V

R = 200 Ohms


R = V/I

R = 110 V/0.55 A

R = 200 Ohms


Answer: 200 Ohms


b) How much power does the toaster use?


P = VI

P = (110 V)(0.55 A)

P = 60.5 W


Answer: 60.5 W


9. Your parents complain that you used 1500 J of energy when you left the light on in your room. If it is a 120 W light bulb, how long did you leave it on?


t = E/P

t = 1500J

t = 12.5s


Answer: 12.5s


10. A portable heater uses 600 000 J of energy in an hour. It is plugged into a wall voltage of 110 V. What is the electric current?


E = 600 000 J

t = 1 hour

V = 110 V


I = E/Vt

I = 600, 000 J/ (110V)(3600s)

I = 1.52 A


Answer: 1.52 A