Physics Review Electric Circuits

Which of the following statements are false about an electric potential or electric potential difference?

-Electric potential can also be expressed in units of Joules. -The electric potential of a charge at a given location provides a measure of the rate at which charge flows past that point. -As a + charge moves in the same direction as an electric field, it gains electric potential. -The electric potential difference between two points is simply the difference in potential energy possessed by charge between those two points.

Which of the following statements are true about an electric potential or electric potential difference?

-Electric potential: expressed in volts. -Work must be done on a + charge to move it against (i.e., in the opposite direction of) an electric field. - If a unit of charge has a high electric potential at any given location, then that charge possesses a large amount of electric potential energy at that location. -The + terminal of a battery is a location with a higher electric potential than the - terminal of a battery. -Charge flowing through a battery will experience a gain in electric potential. -A 6-Volt battery would provide 12 Joules of energy to 2 Coulombs of charge as it is moved from the - to the + terminal.

Which of the following statements are true about an electric circuit?

-Electrons are the mobile charge carriers in an electric circuit. -Charge is supplied with energy in the internal circuit and the energy is transformed into other forms in the external circuit. -The + terminal is the location of high energy in an electric circuit.

Which of the following statements are false about an electric circuit?

-The path of charge flow from the + to the - terminal of the circuit can consist of nonconductive material. -In an electric circuit of an automobile, the 12-Volt car battery is sometimes referred to as the internal circuit because it is located inside of the hood of the car. -Charge is consumed as it moves through the energy-transforming devices of the external circuit. For instance, the amount of charge entering a light bulb in a second is less than that which exits the light bulb in a second. -A battery is used to power a flashlight circuit. When the battery no longer works, it is because it has run out of charge.

Unit equivalencies

1 Ampere = 1 Coulomb / second 1 Watt = 1 Volt • Coulomb / second 1 Joule / Ohm = 1 Ampere • Coulomb 1 Joule • Ohm = 1 Volt2 • second

Ampere:

Coulomb/second

Which of the following statements are false about electric current?

Electric current and drift speed are synonymous terms. Electric current is defined as the number of Coulombs of charge which move past a point on a circuit. Electric current provides a measure of how fast charge moves between two points on a circuit. The electric current diminishes in value as charge progresses to locations further and further from the + terminal of the battery. Suppose a miniature light bulb is connected to a battery in a circuit. A light bulb with a greater resistance will have a greater current.

Which of the following statements are true about electric current?

Electric current is measured in units of Amperes. Electric current is equal to the number of Coulombs of charge which move past a point on a circuit per unit of time. The electric current in a circuit will increase as the electric potential impressed across a circuit is increased. The electric current in a circuit will triple in value as the electric potential impressed across a circuit is increased by a factor of three. Wider conducting wires are capable of carrying larger currents. If one starts getting technical about the meaning of electric current, one could argue that electric current is not something that flows past a point on a circuit, but rather something that exists to a given measure at a point on a circuit.

Which of the following statements are true about a parallel circuit?

Parallel circuits are characterized by the fact that there are multiple pathways by which charge can travel from the + terminal to the - terminal. The total current in a circuit increases as more and more resistors are placed in parallel in the circuit. Suppose that three identical resistors with a resistance of 3-ohms are placed in parallel with a 12-Volt battery. The electric potential difference across each resistor is 12 Volts. Suppose that two identical resistors are placed in parallel with a 12-Volt battery. The overall current in the circuit is 6 amps. The resistance of each resistor is 4 ohms.

Which of the following statements are false about electric power and electric potential energy?

Power is the amount of energy used by an electrical appliance A kiloWatt•hour is a unit of electric power. A 60-Watt light bulb would consume 30 Joules of electrical energy in 2 seconds. A 120-Watt light bulb would consume 1200 Joules of electrical energy in 6 seconds. Charge has the greatest amount of electric potential energy at the - terminal of the battery. If a 60-Watt light bulb is placed in a 120-Volt circuit, then the current in the light bulb is 2 Amps.

Which of the following statements are true about electric power and electric potential energy?

Power is the rate at which energy is used by an electric circuit. A Joule/second is a unit of power. A charge moving through an electric circuit would gain electric potential energy in the internal circuit and lose electric potential energy in the external circuit. Consider two light bulbs with different power ratings. A 60-Watt light bulb has a greater resistance than a 100-Watt light bulb.

Which of the following statements are true about a series circuit?

Series circuits are characterized by the fact that there is a single pathway by which charge can travel from the + terminal to the - terminal. During any single loop of charge around a series circuit, the charge will pass through each resistor in the circuit. The overall resistance of a circuit increases as more and more resistors are placed in series in the circuit.

Which one of the following occurs when a rechargeable battery is recharged?

The battery, which has run out of chemical reactants, has its chemicals reformed.

Which of the following statements are true about an electric resistance?

The resistance of an electric circuit is a measure of the overall amount of hindrance to the flow of charge through the circuit. A large resistance value indicates that the charge is encountering a relatively large amount of difficulty in moving through the circuit. A 5-ohm resistor would allow a current of 0.5 Amperes when 2.5 Volts is impressed across it. The resistance of a conducting wire will increase as the length of the wire is increased. A threefold increase in the resistance of an electric circuit will result in a threefold decrease in the electric current.

Which of the following statements are false about an electric resistance?

The unit of resistance is the ampere. A 10-ohm resistor would allow a current of 2 Amperes when 5 Volts is impressed across it. The resistance of a conducting wire will increase as the cross-sectional area of the wire is increased. Increasing the resistance of an electric circuit will cause the current in the circuit to increase. A miniature light bulb with a specific resistance is connected to a 1.5-Volt battery to form a circuit. If it were connected to a 6-Volt battery instead, its resistance would increase by a factor of 4.

the same

Voltage=Electric Potential Difference=Electric Pressure

When the light bulb in your lamp no longer works, it is because the bulb has _____

a broken filament which has resulted in an open circuit

Suppose that the current in a typical circuit (DC) is large. This is an indication that ____.

a large number of mobile charge carriers are moving forward per second

The charges that flow through the wires in your home ____

already exist in the wires at your home

A battery is needed in the circuit of your flashlight so that ____

an electric potential difference is maintained across the circuit

purpose of the battery in this circuit is to

b. supply energy to the charge c. move the charge from the - to the + terminal of the battery e. establish an electric potential difference between the + and - terminals

A high voltage battery can ____

do a lot of work on each charge it encounters

When you turn on the room lights, they light immediately. This is best explained by the fact that ____.

electrons present everywhere in the circuit move instantly

Approximately how long would it take an electron to travel from the battery of a car to a head light and back (complete loop)

hours

Electric Circuit as Water Park

pipes which carry the water through the water circuit pump which supplies energy to move the water from the ground to a high elevation: battery the rate at which water is pumped onto the slide: electric current the top of the water slide: positive terminal

Electric Potential:

potential energy possessed per unit of charge at any given location

The drift velocity of mobile charge carriers in electric circuits is ____

very slow; slower than a snail