Physics unit 3

A transformer that always has more turns in the primary than in the secondary coil is called a:

1. step-up transformer

2. mutual induction transformer

3. autotransformer

4. step-down transformer

step-down transformer

In which of the following portions of the x-ray circuit is a step-down transforner located?

1. timer curcuit

2. rectification circuit

3. high-voltage circuit

4. filament circuit

filament circuit

What type of current is needed to properly operate the x-ray tube?

1. alternating

2. any type of current can be used

3. pulsating direct current

4. multidirectional current

pulsating direct current

A step-down transformer:

1. steps down voltage

2. steps down current

3. steps up voltage

4. steps up current

1 and 4

What effect does adjusting the filament control have on the production of x-rays?

1. controls the quantity

2. controls the energy

3. controls the quality

4. controls the penetrating power

controls the quantity

Which of the following are fixed ratio transformer?

1. autotransformer

2. step-up transformer

3. step-down transformer

2 and 3

The purpose of the rheostat in the x-ray circuit is to:

1. minimize electron repulsion

2. monitor tube current

3. alter anode rotation speed

4. adjust filament temperature

adjust filament temperature

Filaments normally operate at these currents to produce termionic emission.

1. 0.5 to 1 amperes

2. 3 to 6 amperes

3. 12 to 15 amperes

4. 20 to 25 amperes

3 to 6 amperes

To prevent electrical shock, which of the following components is grounded?

1. primary of step-up transformer

2. secondary of step-up transformer

3. primary of step-down transformer

4. secondary of step-down transformer

secondary of step-up transformer

The voltage ripple of a high-frequency generator is:

1. 1% or less

2. 12%

3. 50%

4. 100%

1% or less

If 90 kVp is used with a single-phase generator, the minimum electron voltage across the x-ray tube is _____ keV.

1. 0

2. 30

3. 60

4. 90

0

A rectifier allows electrons to flow from _____ in the x-ray tube.

1. anode to anode

2. anode to cathode

3. cathode to cathode

4. cathode to anode

cathode to anode

Full-wave, three-phase 12 pulse units provide an x-ray beam at ____ pulses per second.

1. 60

2. 120

3. 360

4. 720

720

To generate three-phase, twelve-pulse current, how mny recifiers are necessary?

1. 4

2. 6

3. 12

4. 16

12

X-ray tube current is usually measured in which of the following units?

1. amperes (A)

2. ampere-seconds (As)

3. milliamperes (mA)

4. kVp

milliamperes (mA)

The number of impulses through the x-ray tube in 50 milliseconds with a three-phase, twelve-pulse generator is:

1. 6

2. 12

3. 36

4. 72

36

Why are three-phase generators more efficient at producing x-rays than single-phase generators?

1. shorter times are possible

2. voltage never drops to zero

3. current travels faster

4. less heat units are produced

voltage never drops to zero

mA meters are located:

1. in the filament circuit

2. on the secondary side of the step-up transformer

3. on the primary side of the autotransformer

4. on the secondary side of the autotransformer

on the secondary side of the step-up transformer

Wye/star and delta coils are found in:

1. x-ray tube filaments

2. rectifiers

3. three-phase transformer coils

4. timer mechanisms

three-phase transformer coils

Which one of the following is a pre-reading device?

1. ammeter

2. kVp meter

3. mA meter

4. cathode meter

kVp meter

Which one of the following operates on the principle of electromagnetic self-induction?

1. rectifier

2. step-up transformer

3. autotransformer

4. step-down transformer

autotransformer

When the radiographer selects kilovoltage on the control panel, which device is adjusted?

1. step-up transformer

2. induction transformer

3. autotransformer

4. step-down transformer

autotransformer

What type of current is present between the autotransformer and the step-up transformer?

1. alternating current

2. pulsating direct current

3. direct current

4. variable current

alternating current

The first component to receive power in the x-ray circuit is the:

1. mA meter

2. autotransformer

3. rectifier

4. high voltage transformer

autotransformer

The autotransformer has only one:

1. turns ratio

2. coil

3. switch

4. rectifier

coil

Variations in power distribution to the x-ray machine are corrected by the:

1. full-wave rectifier

2. high voltage transformer

3. automatic exposure control

4. line voltage compensator

line voltage compensator

X-ray tubes are operated at or above ____ kVp to avoid being space-chareg limited.

1. 35

2. 40

3. 55

4. 70

40

Which one of the following units is used to measure resistance?

1. volt

2. ohm

3. ampere

4. watt

ohm

The unit of electromotive force is the:

1. ampere

2. volt

3. watt

4. ohm

volt

Which of the following terms describes the amount of electric charge flowing per second?

1. current

2. resistance

3. voltage

4. capacitance

current

What is the unit of electrical current?

1. watt

2. farad

3. volt

4. ampere

ampere

Which one of the following is not related to the force applied to an electrical charge?

1. voltage

2. potential difference

3. amperage

4. electromotive force

amperage

Which one of the following causes electrons to move in a conductor?

1. voltage

2. amperage

3. wattage

4. charge

voltage

If a current of 2 amps flows through a conductor that has a resistance of 8 ohms, what is the voltage across the conductor?

1. 0.25 volts

2. 2 volts

3. 4 volts

4. 16 volts

16 volts

The symbols represents a:

1. diode

2. transformer

3. battery

4. resistor

diode

In a solid conductor, current consists of a flow of moving:

1. photons

2. neutrons

3. protons

4. electrons

electrons

Which of the following are most often classified as electrical conductors?

1. copper

2. rubber

3. water

1 and 3

The electrical resistance which occurs in a conductor is most often manifested as the amount of _____ created.

1. heat

2. electrical noise

3. x-rays

4. magnetism

heat

Ground potential should always equal:

1. negative 1 value

2. plus 1 value

3. alternating positive 1 and negative 1 value

4. zero

zero

Resistance of a conductor is _____ to the length of the conductor.

1. directly proportional

2. inversely proportional

directly proportional

Circuit devices that permit electrons to flow in only one direction are:

1. solid-state diode rectifiers

2. resistors

3. transformers

4. autotransformers

solid-state diode rectifiers

Which of the following devices converts mechanical energy to electrical energy?

1. motor

2. generator

3. stator

4. rotor

generator

The voltage ripple associated with a three-phase, six-pulse rectified generator is about:

1. 4%

2. 13%

3. 32%

4. 100%

13%

Which of the following waveforms shown in the figure below is illustrative of three-phase 12-pulse current?

1. diagram D

2. diagram E

3. diagram F

4. diagram G

diagram E

The voltage across the x-ray tube in three-phase equipment:

1. drops to zero every 180 degrees

2. is 87%-96% of the maximum value

3. is at nearly constant potential

2 and 3

Rectification is employed in the x-ray circuit to:

1. increase voltage in the high-tension transformer

2. heat the filament of the x-ray tube

3. simplify circuitry of the x-ray generator

4. convert alternating current to pulsating direct current

convert alternating current to pulsating direct current

What type of curent is needed to properly operate the x-ray tube?

1. alternating current

2. half-wave alternating

3. pulsating direct current

4. multi-directional current

pulsating direct current

Which type of current produces the highest effective voltage?

1. single phase generators

2. three phase 6 pulse generators

3. three phase 12 pulse generators

4. high frequency generators

high frequency generators

Which one of the folllowing waveforms illustrated below represents alternating current?

1. figure 1

2. figure 2

3. figure 3

4. figure 4

figure 1

A transformer that always has more turns in the primary than in the secondary coil is called a:

1. step-up transformer

2. mutual induction transformer

3. autotransformer

4. step-down transformer

step-down transformer

Which type of transformer power loss is caused by rearranging of the magnetic domains in the core of the transformer producing heat?

1. hysteresis losses

2. magnetic power losses

3. eddy current losses

4. copper losses

hysteresis losses

A transformer that has more turns in the secondary coil than in the primary coil is called a:

1. step-up transformer

2. solenoid

3. step-down transformer

4. filament transformer

step-up transformer

A step-down transformer:

1. steps down voltage

2. steps down current

3. steps up voltage

4. steps up resistance

steps down voltage

How many pulses will be produced in 1/40 second with single phase, full wave-rectification?

3 pulses

How many pulses will be produced in 28 milliseconds with three-phase, six pulse current?

10 pulses

How many pulses will be produced in 55 milliseconds with three-phase, twelve pulse current?

40 pulses

How many pulses will be produced in 1/30 seconds with single phase, full wave-rectification?

4 pulses

What effect does adjusting the filament control have on the production of x-rays?

1. controls the quantity

2. controls the energy

3. controls the quality

4. controls the penetrating power

controls the quantity

To prevent electrical shock, which of the following components is grounded?

1. primary of step-up transformer

2. secondary of step-up transformer

3. primary of step-down transformer

4. secondary of step-down transformer

secondary of step-up transformer

The voltage ripple of a high-frequency generator is:

1. 1% or less

2. 12%

3. 50%

4. 100%

1% or less

If 90 kVp is used with a single-phase generator, the minimum electron voltage across the x-ray tube is ____ keV.

1. 0

2. 30

3. 60

4. 90

0

The line voltage meter is located on the:

1. filament circuit

2. secondary side of the x-ray circuit

3. primary or low voltage circuit

4. primary or high voltage circuit

primary or low voltage circuit

X-ray tubes are operated at or above ____ kVp to avoid being space-charge limited.

1. 35

2. 40

3. 55

4. 70

40

A rectifier allows electrons to flow from _____ in the x-ray tube.

1. anode to anode

2. anode to cathode

3. cathode to cathode

4. cathode to anode

cathode to anode

Full-wave, three-phase 12-pulse units provide an x-ray beam at _____ pulses per second.

1. 60

2. 120

3. 360

4. 720

720

To generate three-phase, twelve-pulse current, how many rectifiers are necessary?

1. 4

2. 6

3. 12

4. 16

12

The autotransformer has ____ winding(s).

1. 1

2. 2

3. 3

4. 4

1

X-ray tube current is usually measured in which of the following units?

1. amperes (A)

2. ampere-seconds (As)

3. milliamperes (mA)

4. milliamperes-seconds (mAs)

5. kVp

milliamperes (mA)

The output current of the autotransformer is:

1. pulsating direct current

2. direct current

3. alternating current

4. high-frequency current

alternating current

Which type of transformer design is the most efficient and most commonly used?

1. air core

2. open core

3. shell type

4. closed one

shell type

The United States operates on 60 cycle current. One cycle of current would equal:

1. 1/120 second

2. 1/60 second

3. 1/4 second

4. 1/2 second

1/60 second

The number of impulses through the x-ray tube in 50 milliseconds with a three-phase, twelve-pulse generator is:

1. 6

2. 12

3. 36

4. 72

36

Which of the following x-ray circuit devices operate(s) on the principle of mutual induction?

1. step-down transformer (filament transformer)

2. step-up transformer

3. autotransformer

4. x-ray tube

1 and 2

Which type of current is needed to properly operate the x-ray tube?

1. alternating current

2. multidirectional current

3. pulsating direct current

4. saturated current

pulsating direct current

The diagram represents a/an:

1. autotransformer

2. step-up/step down transformer

3. variable rheostat

4. rectifier

step-up/step down transformer

The timer is located between the _____ and the ____.

1. filament circuit; exposure switch

2. autotransformer; step-up transformer

3. exposure switch; step-down transformer

4. step-down transformer; x-ray tube

autotransformer; step-up transformer

What factor drops when a falling load generator is used to make an exposure?

1. mA

2. time

3. kVp

4. filtration

mA

Why are three-phase generators more efficient at producing x-rays than single-phase generators?

1. shorter times are possible

2. voltage never drops to zero

3. current travels faster

4. less heat units are produced

voltage never drops to zero

mA meters are located:

1. in the filament circuit

2. on the secondary side of the step-up transformer

3. on the primary side of the autotransformer

4. on the secondary side of the autotransformer

on the secondary side of the step-up transformer

A transformer operates most efficiently on:

1. alternating current

2. direct current

3. pulsating direct current

4. rectified current

alternating current

Which of the following is/are components of the secondary, or high voltage, side of the x-ray circuit?

1. rectification system

2. milliampere (mA) meter

3. filaments

4. kVp meter

1 and 2

Which one of the following meters does not register until an x-ray exposure is made?

1. prereading kilovoltmeter

2. prereading ammeter

3. kilovoltmeter

4. milliammeter

milliammeter

Wye/star and delta coild are found in:

1. x-ray tube filaments

2. rectfiers

3. three-phase transformer coils