Albert Teen

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E = IVt

# E = IVt

### E = IVt

We can calculate the energy transferred in a circuit by using the formula energy = current x voltage x time.

What is the golden rule of physics?

In what form does the energy in a circuit begin if the circuit contains a battery?

True or false? Chemical energy in the battery is transferred to kinetic energy in the circuit.

By what other name do we call the kinetic energy of the electrons?

Electrical current is created from a transfer of energy: It began as chemical energy stored in the battery and was transferred to electrical energy, which is a form of kinetic energy, as electrons move around the circuit.

If you want to work out how much energy is transferred, we need to know the current, the voltage and for how long the current is flowing around the circuit.

1

The formula to work out the energy transferred in a circuit is $E=I\times V\times t$.

$E$ is the energy measured in joules (J),

$I$ is the current measured in amps (A),

$V$ is potential difference measured in volts (V),

$t$ is time measured in seconds (s).

2

How much energy is transferred through a circuit in 2 seconds, if the current is 1 amp and the voltage is 4 volts?

A circuit is switched on for 4 seconds with a current of 4 amps and a voltage of 140 volts. What is the energy transferred?

Remember that $E=I\times V\times t$and that $Q=I\times t$. Now, how can we change the formula for energy to be in terms of $Q$? Remember to simplify the final result.

We can calculate the energy in a circuit in two different ways, depending on what information we have. If we have the current, voltage (or P.D.) and time we can use $E=I\times V\times t$. If we have the charge and the voltage, we can use $E=Q\times V$.

How do we calculate the resistance in a circuit if we have the current and the voltage?

We can work out the voltage, current and resistance, using the $V=IR$ formula.

1

We can make $V$ the object of the formula by using it as it is.

$V=I\times R$

2

Now, make current $I$ the subject.

3

Now, make resistance $R$ the subject.