Video Transcript
The diagram shows a circuit
consisting of a cell and a resistor. The power dissipated by the
resistor is 3.6 watts. What is the current in the
circuit?
In this question, we are asked to
find the current in the circuit. We can begin by recalling that the
power of an electric component is given by the relationship 𝑃 equals 𝐼 times 𝑉,
where 𝑃 is the power, 𝐼 is the current through it, and 𝑉 is the potential
difference across the component. We want to find the current in the
circuit, so let’s rearrange this equation to make 𝐼 the subject. We can do this by dividing both
sides of the equation by 𝑉. Doing this leaves us with the
equation 𝐼 equals 𝑃 divided by 𝑉.
We are told in the question that
the power dissipated by the resistor is 3.6 watts. We can also see that the cell in
the circuit provides a potential difference of 18 volts across the circuit. Since the resistor is the only
other circuit component, the potential difference across the resistor is equal to 18
volts. Substituting these values into our
equation, we find that the current in the resistor is equal to 3.6 watts divided by
18 volts. Completing this calculation, we
find that the current in the resistor is equal to 0.2 amperes. The current in the resistor is the
same as the current in the circuit.
So, our final answer is that the
current in the circuit is equal to 0.2 amperes.
