A single loop of wire with a radius of 7 cm rotates about a diameter in a uniform magnetic field of 1.6 T. To produce a maximum emf of 1 V, it should rotate at what angular speed? Note: angular speed is w = do dt How many different circuit arrangements containing only 3 resistors can be made? An electric company charges 10 cents per kWh. How much does it cost to use a 125W lamp 10 hours a day for 30 days? Note: kWh stands for kilowatt-hour. A kilowatt-hour measures the energy an appliance uses in kilowatts per hour. For example, if you clean your floors with a 1,000-watt vacuum cleaner for one hour, you consume 1 kWh of energy.