* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Problem B - Geneva Area City Schools
Stepper motor wikipedia , lookup
Mains electricity wikipedia , lookup
Skin effect wikipedia , lookup
Three-phase electric power wikipedia , lookup
Switched-mode power supply wikipedia , lookup
Commutator (electric) wikipedia , lookup
Ground (electricity) wikipedia , lookup
Power engineering wikipedia , lookup
Brushed DC electric motor wikipedia , lookup
Wind turbine wikipedia , lookup
Mercury-arc valve wikipedia , lookup
Resistive opto-isolator wikipedia , lookup
Opto-isolator wikipedia , lookup
Two-port network wikipedia , lookup
Electric machine wikipedia , lookup
Buck converter wikipedia , lookup
Current source wikipedia , lookup
Electrification wikipedia , lookup
Earthing system wikipedia , lookup
NAME ______________________________________ DATE _______________ CLASS ____________________ Electromagnetic Induction Problem B rms CURRENTS AND emf PROBLEM A generator with a rms potential difference of 124 V is connected to a 85 resistor. Calculate the maximum output emf. Find the rms current and the maximum ac current in the circuit. SOLUTION Given: ∆Vrms = 124 V Unknown: ∆V max = ? R = 85 Ω Irms = ? Imax = ? Choose the equation(s) or situation: Use the equation for the rms potential difference to find the rms potential difference. ∆Vrms = 0.707 ∆Vmax Use the equation for rms current to find Imax. Irms = 0.707 Imax Rearrange the equation(s) to isolate the unknown(s): Rearrange the definition for resistance to calculate the rms current. ∆Vrms Irms = R Copyright © by Holt, Rinehart and Winston. All rights reserved. Rearrange the equation relating rms current to maximum current so that maximum current is calculated. I s Imax = rm 0.707 Rearrange the equation relating rms potential difference to maximum potential difference so that maximum potential difference is calculated. ∆Vrms ∆Vmax = 0.707 Substitute the values into the equation(s) and solve: ∆Vrms 124 V ∆Vmax = = = 175 V 0.707 0.707 ∆Vrms 124 V Irms = = = 2.1 A R 85 Ω I s 2.1 A = = 3.0 A Imax = rm 0.707 0.707 Evaluate: The maximum values for potential difference and current are a little less than three-halves (1.5 times) the rms values, as expected. Problem B Ch. 20–3 NAME ______________________________________ DATE _______________ CLASS ____________________ ADDITIONAL PRACTICE 1. Suppose you build a hydroelectric turbine in your back yard along a river. The turbine is connected to a generator which can provide a rms potential difference of 320 V onto a 100 Ω load. Calculate the maximum output emf. Find the rms current and the maximum ac current in the circuit. 2. Some wind turbines in the United States can provide an rms current of 1.3 A. Calculate the maximum ac current. 3. In Iceland, people harness geothermal energy by placing pipes deep into the Earth in order to tap hot-water aquifers. Steam from these aquifers spins a turbine that is connected to a generator. Suppose such a generator can provide a rms current of 2.5 A and an rms potential difference of 22 kV. Calculate the maximum ac current. Find the resistance of the load. 4. In Denmark, farmers and people living in rural areas harness wind energy to spin a turbine that is coupled to a generator. The generator can provide an rms current of 1.7 A and an rms potential difference of 220 V. Calculate the maximum ac current and the maximum output emf. 5. A generator can provide a maximum ac current of 1.2 A and a maximum output emf of 211 V. Calculate the rms current, the rms potential difference, and the resistance in the circuit. 6. A generator can provide a maximum output emf of 170 V. Calculate the rms potential difference. 8. Off the western coast of Scotland, turbines are placed in deep ocean water so that ocean waves can spin them. The turbines are connected to a generator, which produces electricity for the locals. These turbines can supply an rms current of 2.1 A on a 16 kΩ load. Calculate the maximum ac current. How much power is supplied? 9. A wind turbine is built to service farmers in England. The turbine is connected to a generator, which can supply a rms current of 1.3 A on a 12 kΩ load. If the rms potential difference is 15.6 kV, find the maximum output emf provided by the wind turbine. Calculate the maximum ac current. How much power is supplied? 10. The total world potential for hydroelectric generation is 1.2 million MW, however, not all of it has been harnessed. Suppose the world’s rms current is 2.2 × 1010 A and it supplies a load of 6.1 × 10–10 Ω. Calculate the total maximum ac current that is harnessed. How much total power can be supplied with this current? Ch. 20–4 Holt Physics Problem Bank Copyright © by Holt, Rinehart and Winston. All rights reserved. 7. Suppose you measure a circuit with a voltmeter. You measure a rms potential difference of 115 V and a resistance of 50.0 Ω. Find the maximum ac current and the rms current in the circuit.