1.
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|
The metal rod in the figure is sliding along a U shaped track as shown. There is a magnetic field in the blue region which is into the figure. What is the direction of the current in the sliding rod?
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| UP |
| DOWN |
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2.
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In the above question, if B=0.4T, L=0.5 m and v= 3 m/s, what is the magnitude of the induced EMF?
|
| 3 volts |
| 2.6 volts |
| 0.6 volts |
| 0 volts |
|
3.
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If the total resistance in the circuit in questions 1 and 2 at a given time is 0.01 ohms what will be the induced current?
|
| 0.6 amps |
| 6 amps |
| 60 amps |
| 600 amps |
|
4.
|
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In questions 1, 2, amd 3 what would be the total magnetic field into the page 12 mm to the left of the moving rod and still in the blue region?
|
| .4 T |
| .399 T |
| .401 T |
| 0 T |
|
5.
|
|
| A |  | B |  |
In which of the above, if any, is the induced current up?
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| A only |
| B only |
| A and B |
| Neither |
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6.
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The current in the wire on the right is increasing, what is the direction of the induced current in the wire loop on the left?
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| clockwise |
| counter-clockwise |
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7.
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The current in the wire on the right is decreasing. What is the direction of the induced current in the wire loop on the left?
|
| clockwise |
| counter-clockwise |
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8.
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If the current in the dark wire loop is counter-clockwise and increasing, what is the direction of the induced current in the smaller loop in its middle?
|
| clockwise |
| counter-clockwise |
|
9.
|
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What will be the direction of the induced current in the small outer loop in the previous question.
|
| clockwise |
| counter-clockwise |
|
10.
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A transformer has an input of 110 DC volts, with 100 turns on the primary and 10 turns on the secondary. What is the output voltage?
|
| 1100 volts |
| 110 volts |
| 11 volts |
| 0 volts |
|
11.
|
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120 volt house current is to be transformed down to 12 volts. What is the ratio of the primary to secondary turns?
|
| 20-1 |
| 10-1 |
| 1-10 |
| 1-20 |
|
12.
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In the preceeding question, if the input current is 1.5 amps then the output current is
|
| .015 amps |
| .15 amps |
| 1.5 amps |
| 15 amps |
|
13.
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A transformer takes 10 volts and 5 amps and changes it to 150 volts. What is the power output of the transformer?
|
| 5 watts |
| 50 watts |
| 150 watts |
| 1500 watts |
|
14.
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A transformer has 150 turns on the primary and 20 on the secondary. 100 volts and 10 amps will be changed to
|
| 13.3 volts and 1.33 amps. |
| 13.3 volts and 75 amps. |
| 750 volts and 1.33 amps. |
| 750 volts and 75 amps. |
|
15.
|
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50 kW are to be transmitted over wires with a resistance of 1.8 ohms at 300 volts. What is the power loss in the wires?
|
| 50 kW |
| 5 kW |
| 5 W |
| 0 W |
|
16.
|
|
50 kW are to be transmitted over wires with a resistance of 1.8 ohms at 30000 volts. What is the power loss in the wires?
|
| 50 kW |
| 5 kW |
| 5 W |
| 0 W |
|
17.
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If the angular frequency, w, is 628 for an electric generator the output frequency is
|
| 25 Hz. |
| 50 Hz. |
| 60 Hz. |
| 75 Hz. |
|
18.
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In the preceeding question, if the number of turns is 50, B is 0.1 T and the coil area is 0.01 m2, what is the peak output voltage?
|
| 220 V |
| 120 V |
| 112 V |
| 36 V |
|
19.
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If the transformer in question 18 is to have a peak output voltage of 90 volts what would be the needed new number of turns?
|
| 25 |
| 60 |
| 100 |
| 124 |
|
20.
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A 100 turn, 60 Hz coil, 6 cm on a side rotates in a 0.2 T magnetic field, what is its peak output voltage?
|
| 12 V |
| 27 V |
| 200 V |
| 270 v |
|
21.
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An inductor (solenoid) of 0.4 H has a current of 10 amps flowing through it. How much energy is stored in it?
|
| 2 J |
| 20 J |
| 200 J |
| 2000 J |
|
22.
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The solenoid in the previous question has 1000 turns and is 0.2 m long, what is the magnetic field B?
|
| 0.004 T |
| 62.8 mT |
| 73.3 mT |
| 0 T |
|
23.
|
|
What is the energy density stored in the magnetic field in the previous question?
|
| 35 J/m3 |
| 275 J/m3 |
| 1571 J/m3 |
| 3500 J/m3 |
|
24.
|
|
A 200 mH inductor is connected to a 50 ohm resistor and both are connected in series through a switch to a 40 volt battery, what is the time constant for this combination?
|
| 4 ms |
| 6 ms |
| 8 ms |
| 10 ms |
|
25.
|
|
When the switch is closed in the circuit in question 24 how long does it take for the current to reach half its final value?
|
| 1.2 ms |
| 2.4 ms |
| 2.8 ms |
| 5.6 ms |
|
26.
|
|
What will be the value of current in question 25?
|
| 0.2 A |
| 0.4 A |
| 0.6 A |
| 0.8 A |
|
27.
|
|
What power is being drawn from the battery at the time determined in question 25?.
|
| 2 W |
| 4 W |
| 8 W |
| 16 W |
|
28.
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What power is being consumed in the resistor at the same time as that in question 27?
|
| 2 W |
| 4 W |
| 8 W |
| 16 W |
