A transformer is to be used to provide power for a computer disk drive that needs 6.4 V (rms) instead of the 120 V (rms) from the wall outlet. The number of turns in the primary is 405, and it delivers 500 mA (the secondary current) at an output voltage of 6.4 V (rms). Find the current in the primary.

The percent efficiency of a machine can never be 100% (or greater), because in the real world some energy is always converted into a. heat b. work c. input force d. output force

Asystematic approach to problem solving is called a (an)

Atoaster oven has a resistive heating element. the average rate at which it dissipates energy as thermal energy is 1.00 \(\rm kw\). in the united states, emf amplitude in household circuits is \(\mathcal e_{\max}\) = 170 \({\rm \; v}\) and the \(\rm ac\) oscillation rate is 60 \(\rm hz\). part a what is the root-mean-square current through the heating element?