The rechargeable batteries for a laptop computer need a much smaller voltage than what a wall socket provides. Therefore, a transformer is plugged into the wall socket and produces the necessary voltage for charging the batteries. The batteries are rated at 9.0 V, and a current of 192 mA is used to charge them. The wall socket provides a voltage of 120 V. (a) Determine the turns ratio of the transformer. (b) What is the current coming from the wall socket? (c) Find the average power delivered by the wall socket and the average power sent to the batteries. (a) N/N₂= Number i (b) lp= (c) Pp= P₁ = Number i Number i Number i Units Units Units Units

A typical wall outlet voltage in the United States is 120 volts. Personal MP3 players require much smaller voltages, typically 302.1 mV. If the number of turns in the primary coil is 35753575, calculate the number of turns NS on the secondary coil of the adapter transformer.

The transformer on a utility pole steps the voltage down from 10000 V to 220 V for use in a college science building. During the day, the transformer delivers electric energy at the rate of 10.0 kW. a) Assuming the transformer to be ideal, during that time, what are the primary and secondary currents in the transformer? b) If the transformer is only 90 % efficient (but still delivers electric power at 10.0 kW), how does its input current compare to the ideal case? c) At what rate is heat lost in the nonideal transformer? d) If you wanted to keep the transformer cool and to do this needed to dissipate half of the joule heating of part c) using water cooling lines (the other half is taken care of by air cooling), what should be the rate of flow (in liters per minute) of water in the lines? Assume the input cool water is at 68∘∘F and the maximum allowable output water temperature is 98∘∘F} .

A transformer outside of a business steps the average voltage down from 3600 V to 120 V. The transformer delivers 1.50 × 106 W to the business at 82.0% efficiency. (Give answers to 3 sig.figs.) Find …     (a) the power delivered to the primary, (b) the current in the primary, and (c) the current in the secondary.