Answer to Question #114344 in Electricity and Magnetism for Yang

Question

Verify my answer?
1.In the U.S.A., most homes receive AC current which is commonly called "120 volts." A graph of the voltage in the wires is over time would show
A. a straight line at 120 V
B. a sin or cos wave with a peak of 120 V and a trough of 0V
C. a sin or cos wave with a peak of more than 120 V and a trough of 0V
D. a sin or cos wave with a peak of more than 120 V and a trough more negative than 120 V
E. a sin or cos wave with a peak of more than 120 V and a trough of -129
=>D
2. In the U.S.A., many homes can have some circuits for appliances that get "240 volts" instead of the regular 120 volts.The increased voltage in these circuits results from
A. The circuit is using all of the coils from the transformer instead of half of the coils
B. The circuit gets current from a different transformer than those who get 120V
C. The circuit has thicker wires for less resistance
D. The appliance(s) plugs into the wall twice
=>A

Answer 1

1.

D. a sin or cos wave with a peak of more than 120 V and a trough more negative than 120 V.

2.

A. The circuit is using all of the coils from the transformer instead of half of the coils.