Power Rating of a Resistor. The power rating of a resistor is the maximum power the resistor can safely dissipate without too great a rise in temperature and hence damage to the resistor. (a) If the power rating of a 15-kΩ resistor is 5.0 W, what is the maximum allowable potential difference across the termi-nals of the resistor?

Video transcript

Hey everyone. So today we're dealing with a problem about circuits. So being told that resistors have a power rating that specifies the maximum power that resistor can dissipate without being damaged. The maximum power. So a wire wound resistor has a resistance of 20 kg homes and a power rating of seven watts with this, we're being asked to determine the greatest potential that can be applied across the resistance terminals. In other words, we're asking we're being asked to find what is the greatest potential difference or voltage that can be applied across the resistor terminals. So we have a power rating of 7. watts. A resistance of 20. Let's write this in blue. A resistance of 20 kg and we're trying to find the voltage. Now before we get started to solving, we need to convert our killer homes to OEMs Because we need everything in our base units. So the resistance is equal to 20 kg OEMs. And we can recall that kilo just means 10 times or times 10 to the power of three. So this will be 20 times 10 to the power of three homes. With this. We can go ahead and use the power formula which states that power is equal to power and wants is equal to V squared divided by are if we want to find fi we can rearrange and get that V is equal to the square root of power times resistance, its power power times resistance substituting in our values. We get the square root of sort of 7.10 watts times 20 Times 10 to the power of three homes. Simplifying this, we get a final answer of 374V. In other words, the greatest potential that can be applied across the resistor terminals. This answer choice c. I hope this helps, and I look forward to seeing you all in the next one.