Deck 13: Generation of Electromotive Force

Question 1

In an AC generator, as the conducting loop makes one full revolution through the magnetic field, the generated current drops to 0 amperes ____________________ times.

Answer 1

two
2

Question 2

The accompanying figure illustrates the positions of a conducting loop as it rotates through a magnetic field. Draw or describe two graphs: one displaying the induced EMF generated if the loop is part of an AC generator; and one displaying the induced EMF generated if the loop is part of a DC generator. Label or indicate points on the graph that correspond to the four orientations of the loop.

Answer 2

For the AC generator, the EMF graph is a sinusoidal curve. The points where curve crosses the axis (0 volts) should be labeled 1, 3, and 1.The peak and trough of the curve should be marked as corresponding to loop orientations 2, and 4. The graph for the DC generator, should resemble two mountains, and should never go below 0. The two mountain peaks should be labeled as orientations 2 and 4. The three points where the EMF falls to zero should be labeled as loop orientations 1, 3, and 1.

Question 3

Most of the electricity produced today is created through the use of alternators and generators, which operate on the principle of ____________________.

Answer 3

induced voltage

Question 4

In an AC generator, the maximum voltage is generated at the moment the conductors that form the sides of the loop are moving parallel to the lines of force.

Question 5

In generators and alternators, powerful ____________________ are used to establish a strong magnetic field.

Question 6

A single loop rotating in a magnetic field can be used to supply a direct current to an external load circuit by means of a simple device known as a(n) ____________________ (a rectifying device).

Question 7

In machines that generate voltage, the strength of the field and the conductor length are fixed quantities.

Question 8

Briefly describe the four factors which determine the amount of induced voltage produced in a conductor.

Question 9

AC generators provide constant voltage and current.

Question 10

In a DC generator, the current in the loop and the load circuit are both DC.