Science PDF - Current Electricity

Summary

This document covers concepts about current electricity, including electric current, electrical power, efficiency formulas, and generating electricity. It includes questions and examples relating to calculating efficiency.

Full Transcript

Current Electricity Electric current is the flow of electricity in a circuit Electrical Power and Efficiency Electric power is when energy is transferred in an electrical circuit. 1 watt / is the same as one Joule. 1 watt = 1000 (KW an hr) Efficiency is the energy of an output...

Current Electricity Electric current is the flow of electricity in a circuit Electrical Power and Efficiency Electric power is when energy is transferred in an electrical circuit. 1 watt / is the same as one Joule. 1 watt = 1000 (KW an hr) Efficiency is the energy of an output that gose into the energy input in a given object. Electrical power: is the rate of electrical energy that is produced or consumed in a given amount of time Efficiency Formula Percent Efficiency = Eout / Ein x 100 G = Given R = Required A = Analysis S = Solve S = Statement 1. What is the percent efficiency of a laptop that used 3500 J, but produses 750 J? G. Eout = 750 A. % Eff = Eout / Ein x 100 = 21.43 Ein = 3500 S. % Eff = 750 / 3500 x 100 = 21.43 R. % Eff? S. The Eff of the laptop is 21.43 Generating Current Electricity To produce electricity, a turbine generator producs mechanical energy to electrical energy. The top genarators are natural gas, coal, nuclear fission, biomass, petroleum, geothermal, and solar thermal. The heat that is produced is to create steam, which moves the blades of the turbine. Current and Voltage Voltage: is the measure of electric potential energy per unit charge. Current: is the flow of electric charge through a circuit. Units: Voltage is measured in volts, Current is measured in amperes. Since this wire is plugged into the 10A terminal, we read the scale using the bottom scale (0-10). Reading = _6_ Since this wire is plugged into the 5 A terminal, we read the scale using the middle scale(0 - 5). Reading = _1_ Resistance The ability of a material to oppose the flow of electric current Greater the resistance, the lower the current, the warmer the material becomes when current flows through it Measured in ohms (Ω) Electric circet Electric cell Unit of measurement is the watt (W) ◆ 1 W = 1 j/s ◆ The higher the “wattage,” the more electrical energy a device produces or uses to operate A Renewable Resource can replenish itself at the rate it is used. A Nonrenewable Resource has a limited supply of uses. Renewable Resources include timber, wind, and solar. Nonrenewable Resources are coal and, natural gas.

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