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Author Question: American power plants usually supply 120 V ac. (a) At what frequency is this voltage supplied? ... (Read 13 times)

SGallaher96

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on: Jul 29, 2018
American power plants usually supply 120 V ac.
 
  (a) At what frequency is this voltage supplied?
  (b) What is the maximum voltage?

Question 2

A galaxy is observed receding from Earth with a speed of 2800 km/s.
 
  If the Hubble constant is 22 km/s per million light-years, estimate how many years ago the light that we presently see from the galaxy actually left the galaxy. (c = 3.00  108 m/s, 1 ly = 9.461  1015 m, 1 y = 3.156  107 s)
  A) 1.4  107 y B) 4.2  107 y C) 4.2  108 y D) 4.2  106 y E) 1.3  108 y


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kingdude89

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Reply #1 on: Jul 29, 2018
Answer to Question 1

(a) 60 Hz (b) 170 V (120 V is the rms voltage)

Answer to Question 2

E


SGallaher96

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Reply #2 on: Jul 29, 2018
Both answers were spot on, thank you once again


kingdude89

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Reply #3 on: Jul 29, 2018
Great! Please up vote :D


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