# Gibilisco - Impedance And Admittance

20 Questions | Total Attempts: 499  Settings  • 1.
The square of an imaginary number
• A.

Can never be negative.

• B.

Can never be positive.

• C.

Can be either positive or negative.

• D.

Is equal to j.

• 2.
A complex number
• A.

Is the same thing as an imaginary number.

• B.

Has a real-number part and an imaginary-number part.

• C.

Is one-dimensional.

• D.

Is a concept reserved for elite mathematicians.

• 3.
What is the sum of 3 + j 7 and −3 − j 7?
• A.

0 + j0

• B.

6 + j14

• C.

−6 − j14

• D.

0 − j14

• 4.
What is (−5 + j 7) − (4 − j5)?
• A.

−1 + j2

• B.

−9 − j2

• C.

−1 − j2

• D.

−9 + j12

• 5.
What is the product (−4 − j 7)(6 − j2)?
• A.

24 − j14

• B.

−38 − j34

• C.

−24 − j14

• D.

−24 + j14

• 6.
What is the magnitude of the vector 18 − j24?
• A.

6

• B.

21

• C.

30

• D.

52

• 7.
The complex impedance value 5 + j0 represents
• A.

A pure resistance.

• B.

A pure inductance.

• C.

A pure capacitance.

• D.

An inductance combined with a capacitance.

• 8.
The complex impedance value 0 − j22 represents
• A.

A pure resistance.

• B.

A pure inductance.

• C.

A pure capacitance.

• D.

An inductance combined with a resistance.

• 9.
What is the absolute-value impedance of 3.0 − j 6.0?
• A.

Z = 9.0 Ω

• B.

Z = 3.0 Ω

• C.

Z = 45 Ω

• D.

Z = 6.7 Ω

• 10.
What is the absolute-value impedance of 50 − j235?
• A.

Z = 240 Ω

• B.

Z = 58,000 Ω

• C.

Z = 285 Ω

• D.

Z =−185 Ω

• 11.
If the center conductor of a coaxial cable is made to have a smaller diameter, all other thingsbeing equal, what will happen to the Zo of the transmission line?
• A.

It will increase.

• B.

It will decrease.

• C.

It will not change.

• D.

There is no way to determine this without knowing the actual dimensions.

• 12.
If a device is said to have an impedance of Z = 100 Ω, you can reasonably expect that thisindicates
• A.

R + jX = 100 + j0.

• B.

R + jX = 0 + j100.

• C.

R + jX = 100 + j100.

• D.

The reactance and the resistance add up to 100 Ω.

• 13.
Suppose a capacitor has a value of 0.050 µF at 665 kHz. What is the capacitive susceptance,stated as an imaginary number?
• A.

BC = j4.79

• B.

BC =−j4.79

• C.

BC = j0.209

• D.

BC =−j 0.209

• 14.
An inductor has a value of 44 mH at 60 Hz. What is the inductive susceptance, stated as animaginary number?
• A.

BL =−j0.060

• B.

BL = j0.060

• C.

BL =−j17

• D.

BL = j17

• 15.
Susceptance and conductance add to form
• A.

Complex impedance.

• B.

Complex inductance.

• C.

Complex reactance.

• D.

• 16.
Absolute-value impedance is equal to the square root of which of the following?
• A.

G^2+ B^2

• B.

R^2+ X^2

• C.

Zo

• D.

Y^2+ R^2

• 17.
Inductive susceptance is defined in
• A.

Imaginary ohms.

• B.

Imaginary henrys.

• C.

• D.

Imaginary siemens.

• 18.
Capacitive susceptance values can be defined by
• A.

Positive real numbers.

• B.

Negative real numbers.

• C.

Positive imaginary numbers.

• D.

Negative imaginary numbers.

• 19.
Which of the following is false?
• A.

BC = 1/XC.

• B.

Complex impedance can be depicted as a vector.

• C.

Characteristic impedance is complex.

• D.

G = 1/R.

• 20.
In general, as the absolute value of the impedance in a circuit increases,
• A.

The flow of ac increases.

• B.

The flow of ac decreases.

• C.

The reactance decreases.

• D.

The resistance decreases.

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