On a dry day, your body can accumulate static charge from walking across a carpet or from brushing your hair. If your body develops a charge of -15 µC (microcoulombs), how many excess electrons has it acquired?

Video transcript

Hey everyone in this example, we're told that the human body can accumulate a static charge from usual activities like walking on a carpet or brushing our hair, we need to find the number of excess electrons If our body develops a charge of negative 24 miller columns. So what we should first recognize is that this is asking us to find the number of electrons. So just and and we would recall that to find N. We're going to take our quantity of charge and divide that by our constant for electrons, which is E. We should recall that E is equal to a value of 1.6 times 10 to the negative 19th power columns per electron. And we're going to start by finding this quantity of charge Q. They give it to us as a negative value. But we should recall that since we're trying to find the number of excess electrons and we want that to be a positive number. So we're going to plug in 24 million columns as a positive value. And we're going to go ahead and recognize that we want quantity of charge to be in units of columns. So we're converting from miller columns, two columns. And we should recall that our prefix milli tells us that for one miller column we have 10 to the negative third power columns. So now that we have miller columns in the numerator and denominator, we can go ahead and cancel them out, leaving us with columns as our final unit. And this is going to give us a value of 0.024 columns as our quantity of charge. Now that we have our proper units for quantity of charge, we can find N by an our numerator plugging in 0.24 columns. And then in the denominator we want to plug in our constant four E, which is 1.6 times 10 to the negative 19th power columns. And so columns will cancel out with columns. And we're going to get that end. Our excess number of electrons is equal to a value of 1.5 times 10 to the 17th power electrons. And so this is the amount of electrons that are A result of our body developing the charge -24 Miller columns. And this is our final answer to complete this example. So I hope that everything we reviewed was clear. If you have any questions, please leave them down below and I will see everyone in the next practice video.