A sinusoidal current i = I cosωt has an rms value I_rms = 2.10 A. (a) What is the current amplitude?

Video transcript

Hi, everyone. In this practice problem, we're being asked to calculate the current amplitude of an electric kettle. We will have a label on the bottom of an electric kettle indicating that it will draw 3.2 amp from 100 and 10 fold ac wall socket. The options given for the current amplitude of the electric kettle are a 3.2 amp B 4.5 amp C 6.7 amp and lastly D 8.4 amp. So in this particular practice problem, the only information given is that the kettle will draw 3.2 M from 100 and 10 fold and these two values are R MS values. So we need to relate Ir MS to the current amplitude. And the current draw it is given to be 3.2 amp by the electric heater is going to be the R MS value. So Ir MS is then going to equals to 3. amp. And in this case, in order for us to get I, we want to recall the formula where I is equals to the square root of two multiplied by Ir MS. So plugging the values in I will then equals to the square of two multiplied by 3.2 amp. And calculating this, we will then get the current amplitude for the electric kennel, which will then equals to 4.5 amp. So that will be the final answer to this particular practice problem which will correspond to option B in our answer choices. So option B with the current amplitude for the electric kennel to be 4. amp will be the answer to this video. If you guys still have any sort of confusion, please make sure to check out our other lesson videos on particular topics and that'll be it for this video. Thank you.