250 2 review

Question 1

A __________ always surrounds a conductor in which an electric current is flowing.

Answer 1

magnetic field

Question 2

The right hand THUMB rule demonstrates:

Answer 2

the direction of magnetic field around a current

Question 3

A magnetic field CANNOT be demonstrated surrounding a conductor in ______________ .

Answer 3

alternating current

Question 4

Whenever a conductor cuts across a magnetic field, or is cut by a magnetic field, __________ is induced into the conductor.

Answer 4

EMF

Question 5

A helix carrying an electric current is a(n):

Answer 5

solenoid

Question 6

When an iron rod is introduced into a solenoid and becomes a electromagnet, the strength of the:

Answer 6

magnetic flux increases

Question 7

The magnitude of the induced EMF depends on the number of lines of force per second called __________ .

Answer 7

flux linkage

Question 8

As the strength of the field in which the conductor cuts increases, the induced EMF __________ .

Answer 8

increases

Question 9

When an EMF is induced in the coil in a direction opposite to the applied EMF, this is termed:

Answer 9

self induction

Question 10

When the conductor moves at an angle away from perpendicular to the lines of force, the strength of the induced EMF:

Answer 10

decreases

Question 11

The magnitude of the current induced decreases as the speed with which a wire cuts the magnetic lines of force:

Answer 11

decreases

Question 12

A simple motor requires which of the following components? (choose 3)

Answer 12

source of current, armature, and powerful magnets

Question 13

A device that converts electrical energy to mechanical energy is a:

Answer 13

motor

Question 14

Which of the following devices utilizes iron bars, source of external current and a rotor is a(n)?

Answer 14

induction motor

Question 15

In order for a generator to continue to produce current it must be attached to a(n):

Answer 15

external circuit of resistance

Question 16

The armature of an AC GENERATOR is connected separately to a (n) ____________ which rotates with the armature in the direction of N to S.

Answer 16

slip rings

Question 17

In an AC circuit, current is hindered by

Answer 17

impedance

Question 18

A 90 cycle high frequency generations has how many alterations of current?

Answer 18

180

Question 19

An opposing flow of current in a circuit creates a hinderance on the flow of current called:

Answer 19

inductance reactance

Question 20

An AC generator produces a current that is:

Answer 20

fluctuates negative to positive

Question 21

How much impedance results in a circuit with 70 volts, 11 amps, 2 ohms of electrical resistance and 3 ohms of inductance reactance with no capacitance reactance?

Answer 21

5 ohms

Question 22

How much voltage is a 60 watt bulb connected to if it utilizing .545 amps?

Answer 22

110

Question 23

T or F, AC generators need an armature to produce an EMF.

Answer 23

True

Question 24

A force that occurs when a magnetic field cuts across another magnetic field is called:

Answer 24

motor effect

Question 25

A fixed transformer that has greater windings on the secondary side is called a __________ and is in the __________ part of the circuit.

Answer 25

step up; voltage

Question 26

How much EMF is produced on the secondary side of a step up transformer with a 1:10,000 when 10 volts are applied?

Answer 26

100 kV

Question 27

Current on the primary side of a step down transformer can be supplied by all of the following except:

Answer 27

autotransformer

Question 28

A closed core transformer is more efficient than an open core transformer as a result of :

Answer 28

less loss of magnetic flux

Question 29

A transformer converts one level of voltage to another level through:

Answer 29

electromagnetic mutual induction

Question 30

A device that regulates current to a step down transformer through variable electromagnetic induction is a:

Answer 30

choke coil

Question 31

How many taps are connected when 60 volts are produced on the secondary and the autotransformer has 220 turns with 110 volts being supplied to the primary side?

Answer 31

120 taps

Question 32

The output of an step down transformer is:

Answer 32

lower amperage

Question 33

Rectification is the process that does which of the following?

Answer 33

a diode redirects filament current before supplying the cathode

Question 34

The PRIMARY disadvantage of self rectification is:

Answer 34

the limitation of high exposure factors

Question 35

In a three phase half wave rectified unit, there are how many rectifiers?

Answer 35

6

Question 36

During the positive half of the cycle, the rectifiers are:

Answer 36

conductive

Question 37

During the negative cycle the reverse voltage is actually higher than the useful voltage. This is caused by:

Answer 37

change in transformer polarity

Question 38

With three-phase full wave rectified equipment, the voltage across the x-ray tube:

Answer 38

drops about 3%

Question 39

In the event that while conducting a spin top test, you see 8 dots on the QC image when 10 was expected which of the following may be the reason?

Answer 39

time inaccuracy

Question 40

In a P-N type rectifier, the side with gallium has a(n) __________________ .

Answer 40

deficiency of electrons

Question 41

Which of the following rectifier type is composed of a valence, forbidden zone and conductive band?

Answer 41

solid state diode

Question 42

A disadvantage of using single phase unit over a three phase unit is:

Answer 42

greater patient dose

Question 43

p-type material

Answer 43

gallium silicon

Question 44

n-type material

Answer 44

arsenic silicon

Question 45

suppress the negative cycle

Answer 45

half wave rectification

Question 46

insufficient potential difference

Answer 46

self rectification

Question 47

What type of rectification occurs when the negative cycle is rerouted to the positive cycle?

Answer 47

full wave rectification