Electric Power - Page 24

Questions
  • A current of 1.6 A is measured through a light-bulb when it is connected across a 110 V source. What power is dissipated by the bulb?
  • What is the current flowing into a desktop computer plugged into a 120-V outlet if the power used is 180 W?
  • A small TV is connected to a 120 volts power supply and draws a current of 1.2 ampere. How much would it cost to use the TV for an average of 2 hours a day for 30 days, if the rate for electrical energy is 10 pesos/kwh?
  • What are the energy conversions that occur when water falls on a paddle wheel connected to a generator that connected to electric lights?
  • A toaster is used an average of 5.0 h a month. The toaster draws 8.0 A of current from a 110 V outlet. If electricity costs 8¢ per kW•h, how much will it cost to operate the toaster for one year?
  • A steam turbine at an electric power plant delivers 4500 kW of power to an electrical generator that converts 95 percent of this mechanical energy into electrical energy. What is the current delivered by the generator if it delivers energy at 3600 V?
  • A bulb is plugged into a 120 volt outlet. The resistance of the bulb is 240 ohms. The current is 0.50 amps. What is the power in watts?
  • A vacuum cleaner's motor has a voltage of 120 V across its terminals and a current of 12 A. How much power does the vacuum cleaner use?
  • At $.06/kWh, how much does it cost to operate a 120 V, 6A circuit for 15 hours?
  • How does a step-up transformer, like the one used in a a battery-powered standby electrical system, not violate the Law of Conservation of energy when it changes 12V from a DC source to 110V of AC supply?
  • How much energy does a 100-W electric bulb consume in two hours?
  • How the voltage increases or decreases with current in a transformer?
  • What is the difference between a step-up and a step-down transformer?
  • A toaster is used an average of 5.0 h a month. The toaster draws 8.0 A of current from 10 V outlet. If electricity costs 8¢ per kWxh. How much will it cost to operate the toaster for one year?
  • An electric heater draws 1100 W of power. Electricity costs 8¢ per kW•h. How much does it cost to operate the heater 3.0 h a day for 30 days?
  • If your computer uses 3.5 A at 110 V, how much will it cost to use the computer for 3 hours a day, seven days a week for two weeks? Assume that the cost of electricity is $0.09 for every kW•h of energy.
  • What units are used to measure the amount of electrical power used in a circuit?
  • In the circuit below, what is the Power (P) of the circiut? With steps please