# Practice Test: Question Set - 16

**1. Household light bulbs have a given power rating, and they operate at 120 V. Which one of the following equations most directly provides the current rating of these light bulbs?**

- (A) P = I

^{2}R

- (B) P = IE

- (C) P = E

^{2}/R

- (D) I = P/E

**2. How much current flows through a 60-W light bulb that is operating at 120 V?**

- (A) 0.5A

- (B) 180 A

- (C) 2 A

- (D) 7200 A

**3. Suppose the zener diode has a breakdown voltage of 10 V and zener resistance of 8.5 W, what is the additional voltage when the current is 20 mA?**

- (A) 0.17 V

- (B) 10.17 V

- (C) 20 V

- (D) 18.8 V

**4. Suppose a voltage source has an ideal voltage of 15V and a source resistance of 0.2W. For what values of load resistance will the voltage source appear stiff?**

- (A) 20 Ohm

- (B) 30 Ohm

- (C) 10 Ohm

- (D) 100 Ohm

**5. A certain power transformer has a turns ratio of 5. What voltage can you expect at the secondary winding when you apply 120 V to the primary winding?**

- (A) 4.73 V

- (B) 0.4 V

- (C) 24 V

- (D) 600 V

**6. The barrier potential across each depletion layer is**

- (A) 0

- (B) 0.8 V

- (C) 0.7 V

- (D) 20 V

**7. The component that forms the electrical connection between the rotating coil of wire in a motor and the external source of electrical energy is called the:**

- (A) Rotor

- (B) Armature

- (C) Battery

- (D) Commutator

**8. Which one of the following statements is true for voltage in a parallel circuit?**

- (A) The
total voltage in a parallel circuit is equal to the average value of the
individual voltages

- (B) The
total voltage in a parallel circuit is always less than the value of the
smallest voltage

- (C) The total
voltage is equal to the sum of the voltages across the individual branches in a
parallel circuit

- (D) The
total voltage of a parallel circuit is the same as the voltages across each
branch

**9. Which one of the following statements is true for the voltages in a series RC circuit?**

- (A) The total
voltage is equal to the sum of the voltages across the resistance and
capacitance

- (B) The
voltage always has the same amplitude and phase for every part of the circuit

- (C) The
total voltage is less than the sum of the voltages across the resistance and
capacitance

- (D) The
total voltage is greater than the sum of the voltages across the resistance and
capacitance

**10. The voltage across a 1N4001 is 0.93V when the current is 1A. What is the power dissipation of the diode for these values?**

- (A) 0.93 W

- (B) 0.93 V

- (C) 1 A

- (D) 9.3 W

**11. A certain electromagnet has 1000 turns of wire. How much current must flow through the coil in order to generate an mmf of 100 ampere-turns?**

- (A) 0.1 A

- (B) 1000 A

- (C) 10 A

- (D) 100 A

**12. The basic unit of measurement for resistance is the:**

- (A) Volt

- (B) Ampere

- (C) Ohm

- (D) Watt

**13. Waveforms are graphs that show:**

- (A) Frequency
on the vertical axis and amplitude on the horizontal axis

- (B) Amplitude on
the vertical axis and frequency on the horizontal axis

- (C) Amplitude
on the vertical axis and the passage of time on the horizontal axis

- (D) The
passage of time on the vertical axis and amplitude on the horizontal axis

**14. Which one of the following kinds of materials has the highest permeability?**

- (A) A diamagnetic
material

- (B) A
ferromagnetic material

- (C) A
paramagnetic material

- (D) All of the
above

**15. How much current flows through a 0.02-H choke that is operating from a 12-V ac, 100-Hz source?**

- (A) 0.02 A

- (B) 0.955 A

- (C) 10 A

- (D) 2.02 A

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