Question 1

Induced voltage is the result of flux cutting across an insulator.

Accepted Answer

A) True 
 B)False

Question 2

To minimize transformer core losses while maintaining high flux density, the core can be made of

Accepted Answer

A)   copper
B)   silver
C)   laminated steel
D)   micaE) B) and C)
F) A) and B)

Question 3

Which of the following is not a typical frequency rating for a power transformer?

Accepted Answer

A)   50 Hz
B)   60 Hz
C)   120 Hz
D)   400 HzE) B) and C)
F) A) and D)

Question 4

What law or theorem states that the reaction vL opposes its cause, which is the change in I?

Accepted Answer

A)   Kirchhoff
B)   Lenz
C)   Thevenin
D)   OhmE) B) and C)
F) A) and C)

Question 5

What is a common piece of test equipment used to increase the ac voltage slowly while monitoring the operation of the equipment being repaired?

Accepted Answer

A)   Function generator
B)   Dc power supply
C)   Variac
D)   Signal generatorE) B) and C)
F) All of the above C

Question 6

Inductance is the ability of a conductor to produce induced voltage when the current varies.

Accepted Answer

A) True 
 B)False

Question 7

When it is necessary to measure the value of an inductor, a ______________ analyzer should be used.

Accepted Answer

The answer of When it is necessary to measure the...

Question 8

What component uses mutual inductance to step up or step down an alternating voltage?

Accepted Answer

A)   Inductor
B)   Capacitor
C)   Resistor
D)   TransformerE) B) and C)
F) A) and B)

Question 9

______________-wound resistors have enough inductance to be evident at radio frequencies.

Accepted Answer

The answer of ______________-wound resistors have enough inductance to be...

Question 10

______________ is the ability of a conductor to produce voltage when the current varies.

Accepted Answer

The answer of ______________ is the ability of a conductor...

Question 11

What is the mutual inductance for two 400-mH coils L1 and L2 that have a coefficient of coupling of 0.3?

Accepted Answer

A)   80 mH
B)   12 mH
C)   120 mH
D)   1.2 HE) None of the above
F) A) and C) C

Question 12

______________ coils are used in rf circuits because higher frequencies need less inductance for the required inductive effect.

Accepted Answer

The answer of ______________ coils are used in rf circuits...

Question 13

With a(n) ______________ the secondary is not electrically isolated.

Accepted Answer

The answer of With a(n) ______________ the secondary is not...

Question 14

With zero losses assumed for the transformer, the power in the secondary

Accepted Answer

A)   is always more than the primary
B)   is always less than the primary
C)   is equal to the power in the primary
D)   is equal to IS times RSE) A) and D)
F) C) and D)

Question 15

The most common trouble in coils is a(n) ______________ winding.

Accepted Answer

The answer of The most common trouble in coils is...

Question 16

Which of the following is a transformer core loss?

Accepted Answer

A)   Wire loss
B)   Dc-current loss
C)   Skin-effect current loss
D)   Hysteresis lossE) B) and C)
F) C) and D)

Question 17

A steady dc current can induce a voltage in a coil.

Accepted Answer

A) True 
 B)False

Question 18

Counter emf or back emf is also known as a bucking voltage.

Accepted Answer

A) True 
 B)False  True

Question 19

When a transformer is used to change or transform a secondary load impedance to a new value as seen by the primary, the secondary impedance is called

Accepted Answer

A)   transformed impedance
B)   reflected impedance
C)   refracted impedance
D)   revised impedanceE) B) and D)
F) None of the above

Question 20

What is it called when a transformer is used to achieve maximum transfer of power from a generator to a load when the generator and load impedances are not the same?

Accepted Answer

A)   Maximum power transfer
B)   Power matching
C)   Impedance matching
D)   Maximum loadingE) B) and D)
F) All of the above

Exam 20: Inductance

Induced voltage is the result of flux cutting across an insulator.

Correct AnswerverifiedShow Answer

To minimize transformer core losses while maintaining high flux density, the core can be made of

Correct AnswerverifiedShow Answer

Which of the following is not a typical frequency rating for a power transformer?

Correct AnswerverifiedShow Answer

What law or theorem states that the reaction vL opposes its cause, which is the change in I?

Correct AnswerverifiedShow Answer

What is a common piece of test equipment used to increase the ac voltage slowly while monitoring the operation of the equipment being repaired?

Correct AnswerverifiedC

Inductance is the ability of a conductor to produce induced voltage when the current varies.

Correct AnswerverifiedShow Answer

When it is necessary to measure the value of an inductor, a ______________ analyzer should be used.

Correct AnswerverifiedShow Answer

What component uses mutual inductance to step up or step down an alternating voltage?

Correct AnswerverifiedShow Answer

______________-wound resistors have enough inductance to be evident at radio frequencies.

Correct AnswerverifiedShow Answer

______________ is the ability of a conductor to produce voltage when the current varies.

Correct AnswerverifiedShow Answer

What is the mutual inductance for two 400-mH coils L1 and L2 that have a coefficient of coupling of 0.3?

Correct AnswerverifiedC

______________ coils are used in rf circuits because higher frequencies need less inductance for the required inductive effect.

Correct AnswerverifiedShow Answer

With a(n) ______________ the secondary is not electrically isolated.

Correct AnswerverifiedShow Answer

With zero losses assumed for the transformer, the power in the secondary

Correct AnswerverifiedShow Answer

The most common trouble in coils is a(n) ______________ winding.

Correct AnswerverifiedShow Answer

Which of the following is a transformer core loss?

Correct AnswerverifiedShow Answer

A steady dc current can induce a voltage in a coil.

Correct AnswerverifiedShow Answer

Counter emf or back emf is also known as a bucking voltage.

Correct AnswerverifiedTrue

When a transformer is used to change or transform a secondary load impedance to a new value as seen by the primary, the secondary impedance is called

Correct AnswerverifiedShow Answer

What is it called when a transformer is used to achieve maximum transfer of power from a generator to a load when the generator and load impedances are not the same?

Correct AnswerverifiedShow Answer

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What law or theorem states that the reaction v_L opposes its cause, which is the change in I?

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C

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What is the mutual inductance for two 400-mH coils L₁ and L₂ that have a coefficient of coupling of 0.3?

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C

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True

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