Units
Ohm's Law
Definitions
Power and Energy
Electric Field
100
The unit used to measure current?
What is an Ampere?
100
What happens to the current in a circuit when the resistance increases.
It decreases.
100
The opposition of a material to current.
What is resistance?
100
The power when the current is 0.55 A and the voltage is 110 V.
What is 60.5 W?
100
The electric field lines due to a source charge is shown below. What is the sign of the source charge?
Positive.
200
The unit used to measure electric potential difference?
What is volts?
200
The Ohm's law equation.
What is R= V/I?
200
Equal to the electric force exerted to a test charge divided by the value of the test charge.
What is electric field?
200
A flashlight bulb uses 2.4 W of power when the current in the bulb is 0.8 A. What is the voltage?
V = P/I = (2.4 W)/(0.8 A) = 3 V
200
The electric field lines due to charges A and B, are shown below. Which charge has a bigger magnitude?
B.
300
The unit used to measure electrical resistance.
What is ohms?
300
What happens to the current through a fixed resistor when the potential difference applied to it is doubled?
It is doubled.
300
The rate at which electric energy is converted to other forms of energy.
What is power?
300
The current flowing in an appliance connected to a 120 V source is 2 A. How many kilowatt-hours of electrical energy does the appliance use in 4 h?
P = IV = (2 A)(120 V) = 240 W = 0.240 kW
E = Pt = (0.240 kW)(4 h) = 0.96 kWh
300
What is the direction of the electrical force exerted by the electric field on an electron in the diagram below?
To the left.
400
The amount of power used when 1 A of current flows through a circuit of 1 V.
What is a watt?
400
The resistance when the voltage is 110 V and the current is 0.2 A
What is 550 ohms?
400
The flow of electric charge through a material.
What is current?
400
A TV with a power rating of 200 W uses 0.8 kWh in one day. For how many hours was the TV on during this day?
t = E/P
= 0.8 kWh/0.200 kW
= 4 h
400
What is the magnitude of a point charge that would create an electric field of 1.00 N/C at points 1.00 m away?
1.11 x 10-10 C
500
The unit which electric companies sell electrical energy to homes and businesses.
What is a kWh?
500
The current in a circuit of 110 V with a resistance 220 ohms.
What is 0.5 A?
500
The difference between the electric potential at two points?
What is the electric potential difference or voltage?
500
A refrigerator operates for 24.0 h every day. If the power rating of the refrigerator is 1200 W, how much electrical energy, in kWh, does the refrigerator use in 30 days?
E = Pt
E = (1.2 kW)(720 h)
= 864 kWh
500
A point charge Q is far from all other charges. At a distance of 2 m from Q, the electric field is 20 N/C. What is the electric field at a distance of 4m from Q?
5 N/C