A 1500-W electric heater is plugged into the outlet of a 120-V ci...

Question

A 1500-W electric heater is plugged into the outlet of a 120-V circuit that has a 20-A circuit breaker. You plug an electric hair dryer into the same outlet. The hair dryer has power settings of 600 W, 900 W, 1200 W, and 1500 W. You start with the hair dryer on the 600-W setting and increase the power setting until the circuit breaker trips. What power setting caused the breaker to trip?

Accepted Answer

Hi everyone today we are going to determine the reading of a washing machine that will blow the fuse when added to the circuit. So first we want to identify all the known information in our problem statement. So we know that the household is connected to a power line of fold which is going to be our fee and our initially amp fuse blows. So we replace it with the regular available five M fuse. So the eye is then going to be five app. So we also have a tv with a power of watt. I'm just going to label that SB one and also a fridge with a power of watt Which are also connected to diffuse. So you want to find the washing machine that will max out this 5M current to diffuse. Okay, so this problem actually uses the assumption that the circuit, it's at steady state and the starting state will draw more current than the steady state. The practical circuit use cutouts that are greater than what is required. A steady operation to accommodate the greater current taken as startup. So the current to diffuse should actually be less than five M. So that it will not blow and the current of five m. Maximum of five M will actually blow the fuse. So the way we want to tackle this problem is to actually determine the power of the washing machine that will blow the fuse by actually calculating the maximum total power that can that can be handled with the maximum current, which is five m. So recall that the power is connected to the potential difference and the current by this formula right here. And the way you can calculate the maximum power with this current is by just plugging in the values With the potential difference of 240 fold and with the current of five amp Then the maximum power is gonna be watt just like so okay, so now that we know what the total power in the circuit is or the maximum that can be handled. We can actually start um sum summing all the different equipments that we have that requires different power outage. Okay, so recall that to do that. We can just pretty much sum each equipment power requirement where P one being the TPP to being in the fridge and P three will be the washing machine that we have or P three is unknown. So the P is was calculated to be 1200 watt. P one is 75 watt and P two is 500. What P three is unknown. So doing rearrangement P. T. Will then be 1200 watt minus 5 75 watt which is actually going to be 625. What that is actually going to be the answer to this particular problem which is going to be corresponding to option C. And that will pretty much be all for this particular problem. If you guys are still confused on this particular example or under similar topics, there are other video lessons on our website that you guys should check out, and that will be all for this example. Thank you.

Watch next