[Music] Hi and welcome back to free sciencelessons.co.uk. By the end of this video, you should be able to calculate the charge flow in a circuit. This is a relatively straightforward topic, but it is important that you learn it. In the last couple of videos, we've been looking at the electric current in series and parallel circuits. So in this video, we're going to take a closer look at what's meant by electric current and then use this to calculate the charge flowing in a circuit. So we're going to start by looking at electrical charge. Electrical charge is measured in kum and that has a symbol capital C. A current of 1 ampere means that we've got one kum of charge flowing per second. So in other words, the size of the electric current is the rate of flow of electrical charge. Now we can use this to work out the charge flow in a circuit. To calculate that we use this equation. The charge flow in kulum equals the current in amp multiplied by the time in seconds. Now you will not be given this equation in the exam. So you need to learn it. Here's a question for you to try. Calculate the charge flowing in this circuit in 20 seconds. Pause the video and try this yourself. Okay. So here's the equation. The charge flow equals the current multiplied by the time. So the current is 0.3 amp and the time is 20 seconds. Putting these into the equation gives us a total charge flow of 6 kum. Here's another question for you. 360 kum of charge flows around a circuit in 400 seconds. Calculate the current in the circuit. Now to answer this question, you'll need to rearrange the equation to calculate the current. So, pause the video now and try this yourself. Okay. So, here's the equation again. The charge flow equals the current multiplied by the time. We need to rearrange this to calculate the current. So, here's the rearranged equation. The current equals the charge flow divided by the time. In this case, the charge flow is 360 kum and the time is 400 seconds. Putting these into the equation gives us a current of 0.9 amp. Remember that you'll find plenty more questions on calculating charge flow in my vision workbook and you can get that by clicking on the link above. Okay. So hopefully now you should be able to calculate the charge flow in a circuit. [Music]