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Electrical energy and power. The power sources supply electrical power to the circuits.

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The load devices consume this power and convert it to other types of energy.

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In the international system, energy is measured in joules of J. Electrical power measures the

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energy that is consumed by a load device or delivered by a power source over a certain

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period. In the international system, it is measured in watts, W.

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Power is calculated as the result of multiplying the voltage of each component by the current that flows through it.

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The unit of energy often used is the kilowatt-hour.

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The Joule effect.

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In fact, all of the elements in a circuit, not just the load devices, consume a small amount of unwanted electrical energy.

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This is a phenomenon known as the Joule effect, and it is due to the resistance of these components.

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In our calculations in this unit, we will consider the resistance of conductors

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and power sources to be negligible. In this exercise you have to calculate the

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current that flows through a 1 watt motor powered by a 5 volt cell. The data is the power

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and the voltage and you do not know the intensity. To calculate it, go through the formula that is

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the word for power is the voltage by the intensity and clarify the equation

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clarify the I the intensity as you have ordered that you don't have any problems

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0.2 is the result remember not given the results in the form of fractions in this

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exercise we have to calculate the energy that consumes is consumed by a heater

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with a power of two kilowatts that runs for three hours first of all the data

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we have the power that is in kilowatts so we put it in watts that is just to

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multiply by 1000 and the time is given to us in three hours we have to put it

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in a unit of the international system that hours remember one hour has three

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three thousand and six hundred seconds so you have in total three hours ten thousand and eight

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hundred seconds and the thing with that we don't know is the energy then we have the formula that

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says that the energy is the power by the time so as we have the units of international system to

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because they are calculate we have to calculate it in joules that is a unit of

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the energy in the international system we have to use watts and seconds just

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making this operation of course you use the calculator you can solve it to

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calculate it in in kilowatts per hour it's easier because you have industry in

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the instructions they give you the power in kilowatts and the time in our

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So you just only have to multiply it and you have the result.