Q.1

A transformer changes ac to dc.

  • True
  • False
Q.2

A transformer responds only to dc.

  • True
  • False
Q.3

A center tap (CT) is a connection at the midpoint of the secondary winding of a transformer.

  • True
  • False
Q.4

The primary is the winding connected to the source, and the secondary is the winding connected to the load.

  • True
  • False
Q.5

An autotransformer is one in which the primary and secondary are automatically coupled.

  • True
  • False
Q.6

A transformer consists of two or more cores that are electrically coupled on a common core.

  • True
  • False
Q.7

In a certain transformer, the input power to the primary isW. If 8.5 W are lost to the winding resistance, what is the output power to the load, neglecting any other issues?

  • 0 W
  • 14.1 W
  • 111.5 W
  • 1,020 W
Q.8

How many primary volts must be applied to a transformer with a turns ratio of 0.1 to obtain a secondary voltage of 9 V?

  • 9 V
  • 90 V
  • 900 V
  • 0.9 V
Q.9

The primary winding of a transformer hasV ac across it. What is the secondary voltage if the turns ratio is 8?

  • 8.8 V
  • 88 V
  • 880 V
  • 8,800 V
Q.10

A transformer

  • changes ac to dc
  • changes dc to ac
  • steps up or down dc voltages
  • steps up or down ac voltages
Q.11

When a 6 V battery is connected across the primary of a transformer with a turns ratio ofthe secondary voltage is

  • 0 V
  • 6 V
  • 48 V
  • 0.75 V
Q.12

In a certain loaded transformer, the secondary voltage is one-fourth the primary voltage. The secondary current is

  • one-fourth the primary current
  • four times the primary current
  • equal to the primary current
  • one-fourth the primary current and equal to the primary current
Q.13

To stepV ac down toV ac, the turns ratio must be

  • 5.5
  • 18
  • 0.18
  • 0.018
Q.14

A transformer

  • changes ac to dc
  • changes dc to ac
  • steps up or down dc voltages
  • steps up or down ac voltages
Q.15

To stepV ac up toV ac, the turns ratio must be

  • 75
  • 750
  • 7.5
  • 0.13
Q.16

What is the coefficient of coupling for a transformer in whichof the total flux generated in the primary does not pass through the secondary?

  • 0.4
  • 4
  • 9.6
  • 0.96
Q.17

A certain transformer has a turns ratio of 1 and a 0.coefficient of coupling. When 2 V ac is applied to the primary, the secondary voltage is

  • 1.7 V
  • 0.85 V
  • 1 V
  • 0 V
Q.18

When a load resistor is connected across the secondary winding of a transformer with a turns ratio ofthe source "sees" a reflective load of

  • 50
  • 12.5
  • 800
  • 0
Q.19

What kVA rating is required for a transformer that must handle a maximum load current of 8 A with a secondary voltage of 2 kV?

  • 4 kVA
  • 0.25 kVA
  • 16 kVA
  • 8 kVA
Q.20

IfW of power are applied to the primary of an ideal transformer with a turns ratio ofthe power delivered to the secondary load is

  • 25 W
  • 0 W
  • 250 W
  • 2.5 W
Q.21

IfW of power are applied to the primary of an ideal transformer with a turns ratio ofthe power delivered to the secondary load is

  • 25 W
  • 0 W
  • 250 W
  • 2.5 W
Q.22

The primary winding of a power transformer should always be

  • open
  • shorted
  • switched
  • fused
Q.23

When a load resistor is connected across the secondary winding of a transformer with a turns ratio ofthe source "sees" a reflective load of

  • 50
  • 12.5
  • 800
  • 0
Q.24

When the turns ratio of a transformer isand the primary ac voltage isV, the secondary voltage is

  • 12 V
  • 120 V
  • 240 V
  • 2,400 V
Q.25

A transformer has a 1:6 turns ratio and a secondary coil load resistance of. The load resistance as seen by the source is

  • 1.3
  • 7.8
  • 78
  • 13
Q.26

The primary winding of a power transformer should always be

  • open
  • shorted
  • switched
  • fused
Q.27

A certain transformer hasturns in the primary winding and 2,turns in the secondary winding. The turns ratio is

  • 0.2
  • 0.4
  • 5
  • 25
Q.28

A certain transformer hasturns in the primary winding and 2,turns in the secondary winding. The turns ratio is

  • 0.2
  • 0.4
  • 5
  • 25
Q.29

A transformer with aV primary has a 15:1 turns ratio. The load resistance, RL, is. What is the approximate voltage across the load?

  • 7.3 V
  • 73 V
  • 88 V
  • 880 V
Q.30

A certain transformer hasturns in the primary winding and 2,turns in the secondary winding. The turns ratio is

  • 0.2
  • 0.4
  • 5
  • 25
0 h : 0 m : 1 s