Video Transcript
The diagram shows a circuit
consisting of a battery and a resistor. What is the resistance of the
resistor?
In this question, we are given a
diagram of an electric circuit that consists of a battery and a resistor. The battery provides a potential
difference of 24 volts to the circuit and the current in the circuit is three
amperes. We are asked to find the resistance
of the resistor. In order to do this, we’re going to
use Ohm’s law. Ohm’s law states that the potential
difference across a component is equal to the current through the component
multiplied by the electrical resistance of the component. As an equation, 𝑉 equals 𝐼 times
𝑅, where 𝑉 is the potential difference, 𝐼 is the current, and 𝑅 is the
resistance.
In this question, we are concerned
with finding the electrical resistance. So let’s rearrange this equation to
get the resistance by itself on one side. We can do this by dividing both
sides of the equation by the current 𝐼. These 𝐼-terms on the right-hand
side cancel, giving us an equation for resistance. The resistance is equal to the
potential difference divided by the current.
Now that we have the right
equation, we can answer this question. The battery provides a potential
difference of 24 volts to the resistor. So the potential difference across
the resistor, 𝑉, is equal to 24 volts. The current through the resistor 𝐼
is three amperes. Let’s recall that electrical
resistance is measured in units of ohms, which are represented by this symbol. With the values of 𝑉 and 𝐼
substituted into this equation, we see that the resistance of the resistor is equal
to 24 volts divided by three amps, which is equal to eight ohms. This is the resistance of the
resistor.
