The metric unit of work is the ____ and the metric unit of power is the ____.

Mathematically, work is calculated from knowledge of the force (F) which acts upon an object, the displacement (d) which the force causes, and the angle () between the force and displacement vectors. The formula is

W = F • d • cosine()

Mathematically, power is a rate quantity - a time-based quantity. It is the rate at which a force does work upon a charge. Power (P) is calculated from knowledge of the work done (W) and the time (t) required to do this work. The formula is

It is often the case that the units of a quantity can be determined from the formula for the quantity. In the case of work, the units would be a unit of force multiplied by a unit of displacement. This would be a Newton • meter, abbreviated N•m. The unit Joule, abbreviated J, is defined to be equivalent to a N•m. Thus, Joule is the standard unit of work in the metric system.

In the case of power, the units would be a unit of work divided by a unit of time. This would be a Joule/second, abbreviated J/s. The unit Joule/second is defined to be equivalent to a Watt. Thus, Watt is the standard unit of power in the metric system.

What is the unit of work and the unit of power?

When you pay your electric bill, you pay for the number of kilowatt x hours of electricity which you use. You are paying for the ___ you use.

Mathematically, power is a rate quantity - a time-based quantity. It is the rate at which a force does work upon a charge. Power (P) is calculated from knowledge of the work done (W) and the time (t) required to do this work. The formula is

The unit kilowatt x hour is a unit of power multiplied by a unit of time. The equation in the Formula Fix section above relates power, work and time. This equation can be rearranged to the form W = P •t. Once done, it is clear that a unit of power multiplied by a unit of time would be a unit of work. So kilowatt x hour is a unit of work or energy. This makes sense because your electric bill gives an indication of the quantity of electrical energy which a household consumes each month.

What is a kilowatt•hour?

Two identical light bulbs are turned on in a house. If one is left on for twice the time, it will ____ as the other.

Mathematically, power is a rate quantity - a time-based quantity. It is the rate at which work is done by a battery upon a charge. Power is also the rate at which energy is used up by an appliance. Power (P) is calculated from knowledge of the work done (W) and the time (t) required to do this work. The formula is

P = W / t = E / t

Appliances which are on in a home use up electrical energy. Another way to put it is that they transform the electrical energy into other forms of energy such as light energy, thermal energy, and mechanical energy. The rate at which the energy is used up is known as the power. A light bulb is rated in terms of the rate at which it uses energy when plugged into a 110-120 volt U.S. outlet. A 60-Watt bulb will use 60 Joules of electrical energy per second. Leaving the bulb on for two hours will not change the wattage of the bulb. It will remain a 60-Watt bulb for its entire lifetime. A rearrangement of the equation in the Formula Fix section above would yield the relationship

E = P • t

As can be seen in this equation, a doubling of the time which a light bulb is on will double the amount of energy used by the bulb.

Current electricity language can be confusing. Confusing or not, it is the language which will be used to describe and explain the physics of electric circuits. Many of the incorrect responses to this question represent a statement which reflects a lack of understanding of terms. You may find it useful (particularly if you have missed this question frequently) to develop a list of terms with their definition, equation, units and a short and meaningful description. The following terms should be included on the list: current, potential difference (voltage), potential energy (work), electric power, charge, current and resistance.

How is power, energy (work) and time related?

A 12-Volt battery will ____.

Definition of Electric Potential:

Electric potential is a location dependent quantity which expresses the amount of potential energy per unit of charge at a specified location. Mathematically, electric potential is the quantity of energy per unit of charge. Typical units on electric potential are Joules per Coulomb (abbreviated J/C). The term voltage is sometimes used in place of the phrase electric potential. Because of the use of the term voltage, the units of electric potential is the Volt. One volt is equivalent to a J/C.

As mentioned in the Define Help section above, electric potential expresses the amount of electric potential energy per unit of charge at a specific location. The battery's role is to do work upon an charge to move it from the low energy terminal to the high energy terminal. By doing so, the charge becomes energized, pressurized and ready to flow through the external circuit. A 12-Volt battery will provide each Coulomb of charge 12 Joules of electric potential energy. In this sense, the voltage of a battery provides a rating of how much energy it provides to each Coulomb of charge that it would move from low energy to high energy.

The current electricity module is filled with a larger than usual number of vocabulary terms. Many of the terms are abstract and confusing. Yet the terms will become the language used to discuss the physics of electric circuits. In most cases, the terms are measurable quantities which have a mathematical side to them. It would be a wise idea to begin now to develop a list of the main vocabulary terms. For each term: write its definition, write any synonyms used in its place, state the units of measurement, write any relevant equations which relate the quantity to other quantities, and include any descriptive notes which would help you make meaning of the term. The following terms should be included on the list: current, potential difference (voltage), potential energy (work), electric power, resistance.

How is work (energy), voltage and charge related to each other?

A battery does 6 Joules of work on each coulomb of charge that it encounters. What is the voltage of the battery?

Definition of Electric Potential:

Electric potential is a location dependent quantity which expresses the amount of potential energy per unit of charge at a specified location. Mathematically, electric potential is the quantity of energy per unit of charge. Typical units on electric potential are Joules per Coulomb (abbreviated J/C). The term voltage is sometimes used in place of the phrase electric potential. Because of the use of the term voltage, the units of electric potential is the Volt. One volt is equivalent to a J/C.

The role of a battery in an electric circuit is to do work upon an electric charge. By doing work upon the charge, the battery moves charge to a high energy and high potential location. Once there, the charge can naturally move through the external circuit back to the low energy terminal. As mentioned in the Define Help section above, electric potential or voltage describes the amount of electric potential energy per unit of charge at a specific location. A 12-volt battery provides 12 Joules of energy for every 1 Coulomb of charge which it moves from the low energy location to the high energy location. As such, the voltage rating of a battery simply describes the energy change of every coulomb of charge which is moved between terminals.

How is work (energy), voltage and charge related to each other?

A battery does 6 Joules of work for every 4 C of charge that it encounters during a 2-second time period. What is the voltage of the battery?

Definition of Electric Potential:

Electric potential is a location dependent quantity which expresses the amount of potential energy per unit of charge at a specified location. Mathematically, electric potential is the quantity of energy per unit of charge. Typical units on electric potential are Joules per Coulomb (abbreviated J/C). The term voltage is sometimes used in place of the phrase electric potential. Because of the use of the term voltage, the units of electric potential is the Volt. One volt is equivalent to a J/C.

The role of a battery in an electric circuit is to do work upon an electric charge. By doing work upon the charge, the battery moves charge to a high energy and high potential location. Once there, the charge can naturally move through the external circuit back to the low energy terminal. As mentioned in the Define Help section above, electric potential or voltage describes the amount of electric potential energy per unit of charge at a specific location. A 12-volt battery provides 12 Joules of energy for every 1 Coulomb of charge which it moves from the low energy location to the high energy location. This voltage rating simply expresses the ratio of energy per charge. To say such a battery supplies 12 J of energy per 1 C of charge is the same as saying it supplies 24 J of energy per 2 C of charge. As such, the voltage rating of a battery simply describes the energy change per every coulomb of charge which is moved between terminals.

In this question, the time period over which the battery does work on the charge is mentioned. The time period provides additional information about the process. But don't be fooled! The time has little to do with the battery and its voltage. In fact, a 1.5 Volt battery will not always do this 6 J of work on 4 C of charge in 2 seconds. Sometimes the same work will be done on the same charge in a different time period. The time itself is a descriptor of the power of the circuit - the rate at which the devices (bulbs, heaters, motors and other appliances) in the circuit use the electrical energy. The battery provides the energy at the same rate as it is being used up by the devices in the external circuit. If a bulb with a different power rating is placed in this circuit, then the same work will be done on the same amount of charge in a different amount of time.

How is work (energy), voltage and charge related to each other?

A battery does 24 Joules of work for every 2 C of charge that it encounters during a 4-second time period. What is the voltage of the battery?

Definition of Electric Potential:

Electric potential is a location dependent quantity which expresses the amount of potential energy per unit of charge at a specified location. Mathematically, electric potential is the quantity of energy per unit of charge. Typical units on electric potential are Joules per Coulomb (abbreviated J/C). The term voltage is sometimes used in place of the phrase electric potential. Because of the use of the term voltage, the units of electric potential is the Volt. One volt is equivalent to a J/C.

The role of a battery in an electric circuit is to do work upon an electric charge. By doing work upon the charge, the battery moves charge to a high energy and high potential location. Once there, the charge can naturally move through the external circuit back to the low energy terminal. As mentioned in the Define Help section above, electric potential or voltage describes the amount of electric potential energy per unit of charge at a specific location. A 12-volt battery provides 12 Joules of energy for every 1 Coulomb of charge which it moves from the low energy location to the high energy location. This voltage rating simply expresses the ratio of energy per charge. To say such a battery supplies 12 J of energy per 1 C of charge is the same as saying it supplies 24 J of energy per 2 C of charge. As such, the voltage rating of a battery simply describes the energy change per every coulomb of charge which is moved between terminals.

In this question, the time period over which the battery does work on the charge is mentioned. The time period provides additional information about the process. But don't be fooled! The time has little to do with the battery and its voltage. In fact, a 12 Volt battery will not always do this 24 J of work on 2 C of charge in 4 seconds. Sometimes the same work will be done on the same charge in a different time period. The time itself is a descriptor of the power of the circuit - the rate at which the devices (bulbs, heaters, motors and other appliances) in the circuit use the electrical energy. The battery provides the energy at the same rate as it is being used up by the devices in the external circuit. If a bulb with a different power rating is placed in this circuit, then the same work will be done on the same amount of charge in a different amount of time.

How is work (energy), voltage and charge related to each other?

When plugged into a 120-Volt outlet, a light bulb does 100 Joules of work each second that it is lit. What is the power of the light bulb?

Definition of Power:

Power is the rate at which work is done upon an object. As applied to electrical circuits, electrical power is the rate at which work is done upon a charge. The work done upon a charge results in a change in the electric potential energy of the charge. Thus, power can be defined in electrical terms as the rate at which a charge changes its electric potential energy.

Power (P) is the rate at which a charge changes its electric potential energy (E) as it moves from one location to another location. This can be expressed as

P = E / t

Light bulbs have a power rating. The power rating describes the rate at which the light bulbs uses the electrical energy of moving charge to produce light energy (and thermal energy). A 60-Watt bulb will consume 60 J of electrical energy per second of time when plugged into a typical U.S. outlet. As descried in the Formula Fix section above, the power rating is simply the ratio of energy used per time of use.

How is power, energy (work) and time related?

A light bulb does 300 Joules of work over a 5 second time period. What is the power of the light bulb?

Definition of Power:

Power is the rate at which work is done upon an object. As applied to electrical circuits, electrical power is the rate at which work is done upon a charge. The work done upon a charge results in a change in the electric potential energy of the charge. Thus, power can be defined in electrical terms as the rate at which a charge changes its electric potential energy.

Power (P) is the rate at which a charge changes its electric potential energy (E) as it moves from one location to another location. This can be expressed as

P = E / t

Light bulbs have a power rating. The power rating describes the rate at which the light bulbs uses the electrical energy of moving charge to produce light energy (and thermal energy). A 60-Watt bulb will consume 60 J of electrical energy per second of time when plugged into a typical U.S. outlet. As descried in the Formula Fix section above, the power rating is simply the ratio of energy used per time of use.

How is power, energy (work) and time related?

A certain electrical circuit contains a battery, wires and a light bulb. If potential energy is gained by charges at the battery, charges lose potential energy ____.

In a sense, circuits are all about energy. Energy is introduced into the circuit by the battery. The battery acts as a charge pump in a circuit, moving charge between terminals so as to supply an electric potential difference across the two ends of a circuit. It serves an analogous role as the water pump in a water circuit. The battery moves the charge from low energy to high energy much like a water pump moves water from low energy to high energy. Both processes require the input of energy to the system. If the battery is the energy input location of a circuit, then the energy output is the light bulb. As charge moves through the light bulb, its electric potential energy is dramatically decreased as light energy is produced. In this sense, circuits are all about energy - energy in at the battery and energy out at the light bulb.

The above discussion ignores the fact that life does not always turn out as ideally as dreamed. The lives of charge flow in electric circuits is plagued the reality of inefficiency. Light bulbs don't simply produce light energy; they also get hot and produce thermal energy. This represents a waste of energy as the bulb's lack of efficiently results in the production of an unintended form of energy. Also, the wires are not exactly efficient conduits through which charge flows. Wires heat up as well and cause a very small loss of energy.

At what locations in a circuit will a charge lose its energy?