Video Transcript
How many milliamperes are there in one ampere?
Let’s begin by reminding ourselves that the ampere is the SI unit of electric current. We can also recall that a current is just a rate of flow of electric charge over time. So if there’s a current of one ampere at a particular point in a circuit, then this means that in a time interval of one second, a total charge of one coulomb flows through that point. We can express this mathematically by saying that one ampere is equal to one coulomb per second.
Now this question is asking us how many milliamperes there are in one ampere. In order to answer this, we need to recall that the unit prefix milli- means a factor of one thousandth or a factor of one divided by 1000. This means then that one milliampere must be equal to one thousandth of an ampere. And we can express that mathematically by saying that one milliampere is equal to one ampere multiplied by one over 1000. If we then multiply both sides of this equation by 1000, we end up with this equation here.
Notice that on the right-hand side, we’ve got a factor of one over 1000 and a factor of 1000. We can see then that these two terms will cancel each other out because 1000 divided by 1000 is simply equal to one. On the left-hand side, 1000 multiplied by one milliampere is simply equal to 1000 milliamperes. We found then that 1000 milliamperes is equal to one ampere. We could also express this statement as saying that in each one ampere, there are 1000 milliamperes.
Our answer to this question then is that the number of milliamperes that there are in one ampere is equal to 1000.
