91Ó°ÊÓ

A certain circuit breaker trips when the rms current is 15.0 A. What is the corresponding peak current?

Military aircraft use 400 -Hz AC power, because it is possible to design lighter-weight equipment at this higher frequency. What is the time for one complete cycle of this power?

A North American tourist takes his 25.0-W, 120-V AC razor to Europe, finds a special adapter, and plugs it into 240 VAC. Assuming constant resistance, what power does the razor consume as it is ruined?

A small office-building air conditioner operates on 408-V AC and consumes \(50.0 \mathrm{kW}\). (a) What is its effective resistance? (b) What is the cost of running the air conditioner during a hot summer month when it is on 8.00 h per day for 30 days and electricity costs 9.00 cents/kW \(\cdot\) h?

What is the peak power consumption of a \(120-\mathrm{V} \mathrm{AC}\) microwave oven that draws \(10.0 \mathrm{A} ?\)

What is the peak current through a 500 -W room heater that operates on 120 -V AC power?

Two different electrical devices have the same power consumption, but one is meant to be operated on \(120-\mathrm{V} \mathrm{AC}\) and the other on \(240-\mathrm{V} \mathrm{AC}\). (a) What is the ratio of their resistances? (b) What is the ratio of their currents? (c) Assuming its resistance is unaffected, by what factor will the power increase if a \(120-\mathrm{V}\) AC device is connected to \(240-\mathrm{V}\) AC?

(a) How much power is dissipated in a short circuit of \(240-\mathrm{V} \mathrm{AC}\) through a resistance of \(0.250 \Omega ?(\mathrm{b}) \mathrm{What}\) current flows?

What voltage is involved in a 1.44 -kW short circuit through a \(0.100-\Omega\) resistance?

Find the current through a person and identify the likely effect on her if she touches a \(120-\mathrm{V}\) AC source: (a) if she is standing on a rubber mat and offers a total resistance of \(300 \mathrm{k} \Omega ;\) (b) if she is standing barefoot on wet grass and has a resistance of only \(4000 \mathrm{k} \Omega\).