The electric train model transformer plugs into 220-V ac and draws 0.35 A while supplying 10.5 A to the train, (a) What voltage is present across the tracks? (b) Is the transformer step-up or step- down?

If the voltage of the primary coil in a transformer is twice that of the voltage in the secondary coil, then the current in the secondary coil is ____ that of the primary coil.   Question 4 options:   four times   twice as much   the same as   1/2 as much   1/4 as much   None of the other responses are correct.

Does a transformer work when a DC current flows through the primary? If not, why?

A transformer is to be used to provide power for a computer disk drive that needs 5.6 V (rms) instead of the 120 V (rms) from the wall outlet. The number of turns in the primary is 420, and it delivers 500 mA (the secondary current) at an output voltage of 5.6 V (rms). (a) Should the transformer have more turns in the secondary compared to the primary, or fewer turns? O There should be more turns in the secondary. O There should be fewer turns in the secondary. (b) Find the current in the primary. (c) Find the number of turns in the secondary. turns