Computer Science Engineering Electronic Principles - Set 13 - ObjectiveBooks

# 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 = E2/R
(C) P = I2R
(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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