# Practice Test: Question Set - 13

**1. Which one of the following phrases most accurately describes a purely inductive circuit?**

- (A) Resistances
provide the only opposition to current flow

- (B) Inductive
reactance provides the only opposition to current flow

- (C) Combinations
of resistance and inductive reactance provide any opposition to current flow

- (D) The
ac voltage lags the current by 90 degree

**2. Which one of the following is most likely used for measuring the rate of electron flow?**

- (A) Voltmeter

- (B) Ammeter

- (C) Wattmeter

- (D) Ohmmeter

**3. Doubling the operating voltage of a purely capacitive circuit:**

- (A) Has no
effect on the capacitive reactance

- (B) Doubles
the amount of capacitive reactance

- (C) Multiplies
the capacitive reactance by 7

- (D) Cuts the capacitive
reactance in half

**4. Doubling the operating frequency of a purely inductive circuit:**

- (A) Doubles
the amount of current through the inductors

- (B) Has
no effect on the current through the inductors

- (C) Cuts
the current through the inductors one-half

- (D) Increases
the current, but by an amount that can be determined only by doing a complete
analysis of the circuit

**5. A dielectric material is:**

- (A) A
good conductor

- (B) A
good insulator

- (C) A
poor conductor of electrostatic fields

- (D) A
good conductor of magnetic fields

**6. Suppose a step-down transformer has a turns ration of 5:1. If the secondary current is 1A rms, what is the primary-current?**

- (A) 0.3 A

- (B) 0.2 A

- (C) 0.4 A

- (D) 0.6 A

**7. What is the capacitive reactance of a 0.1 micro F capacitor that is operating at 1000 Hz?**

- (A) Less than 1
Ohm

- (B) 1590 Ohm

- (C) 312 Ohm

- (D) 690 Ohm

**8. Which one of the following equations most directly determines the power dissipation of a resistance when you know the power dissipation of a resistance when you know the voltage drop and current?**

- (A) P = IE

- (B) P = E

^{2}/R

- (C) P = I

^{2}R

- (D) I = P/E

**9. The total inductance of a series inductor circuit is:**

- (A) Equal
to the sum of the individual inductance values

- (B) Equal
to the sum of the individual inductive-reactance values

- (C) Less
than the value of the smallest inductor

- (D) Equal
to the source voltage divided by total current

**10. The saturation point is approximately the same as**

- (A) Cutoff point

- (B) Lower end of
the load line

- (C) Upper end of
the load line

- (D) Infinity

**11. The total impedance of a parallel RLC circuit:**

- (A) Always
increases as the applied frequency increases

- (B) Is
equal to the sum of the values of resistance, inductive reactance and
capacitive reactance

- (C) Always
decreases as the applied frequency increases

- (D) Is
maximum at the resonant frequency

**12. Current is**

- (A) The
flow of charged particles through a material

- (B) An
imbalance of electrical charges

- (C) The force
that causes electrons to flow

- (D) The number
of free electrons in an atom

**13. Which one of the following phrases best describes residual magnetism?**

- (A) Magnetism that
remains in the core of an electromagnet after the current through the coil is
turned off

- (B) The
force of attraction between the poles of a permanent and temporary magnetic
field

- (C) The
amount of magnetic flux that is not confined to the core material of an
electromagnet

- (D) The
circular magnetic field that surrounds a conductor carrying a current

**14. The secondary voltage for a certain power transformer is twice the voltage applied to the primary. The current flowing in the secondary winding will be:**

- (A) One-half the
primary current

- (B) Same as the
primary current

- (C) Twice the
primary current

- (D) No more than
10% less than the primary current

**15. Molecule is**

- (A) The
smallest particle of a substance that retains the properties of that substance

- (B) An atom that
has a shortage of electrons in its outer orbit

- (C) An
atom that has an excessive number of electrons in its outer orbit

- (D) An
atom that flows whenever there is an imbalance of electrical charges between
two points

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