OBJECTIVE QUESTIONS FROM BASIC ELECTRICAL ENGINEERING: 7

OBJECTIVE QUESTIONS FROM BASIC ELECTRICAL ENGINEERING:

[1] The main advantage of air as a dielectric material for capacitors is

A.  Has a high dielectric constant

B.  Is not physically dense

C.  Has low loss

D.  Allows for large capacitance in a small volume

Ans:C

[2] Which of the following is a polarized capacitor?

A.  Paper

B.  Mica

C.  Inter electrode

D.  Electrolytic

 

Ans:D

[3] In a 117Vrms utility circuit, the positive peak voltage is approximately

A.  82.7V

B.  165V

C.  234V

D.  331V

Ans:B

 
[4] If a capacitor has  a negative temperature coefficient then

A. Its capacitance decreases as the temperature rises

B. Its capacitance increases as the temperature rises

C. Its capacitance does not change with temperature

D. It will not work if the temperature is below freezing

Ans: A

[5] Inductors in series, assuming there is no mutual inductance, combine

A.  Like resistors in parallel

B.  Like resistors in series

C.  Like batteries in series with opposite polarities

D.  In a way unlike any other type of component

Ans:B

[6] The five 0.050 μF capacitors are connected in series. The equivalent capacitance is

A.  0.010 μf

B.  0.25 μf

C.  0.50 μf

D.  0.025 μf

Ans: A

 

[7] A material with a high dielectric constant

A.  Acts to increase capacitance per unit volume

B.  Acts to decrease capacitance per unit volume

C.  Has no effect on capacitance

D.  Causes a capacitor to become polarized

Ans:A

 

[8] In a perfect sine wave, the peak to peak amplitude is equal to

A.  Half the peak amplitude

B.  The peak amplitude

C.  1.414 times the peak amplitude

D.  Twice the peak amplitude

Ans: D

 
[9] A triangular wave exhibits

A.  An instantaneous rise and a defined decay

B.  A defined rise and an instantaneous decay

C.  A defined rise and a defined decay, and the two are equal

D.  An instantaneous rise and an instantaneous decay

Ans:C

 

[10] The colour bands on a carbon composition resistor occur in the sequence: yellow, violet, yellow and silver. Its resistance is
(a) 470 KΩ± 47 KΩ
(b) 470 KΩ± 23.5 %
(c) 47 KΩ± 10 % 
(d) 47 KΩ± 5 %

Ans: C

[11] If 120°C of charge passes through an electric conductor in 60 sec, the current in the conductor is
(a) 0.5A
(b) 2A
(c) 3.33mA
(d) 0.3mA

Ans:B

[12] The energy required to move 120 coulomb through 3V is 
(a) 25mJ
(b) 360J
(c) 40J
(d) 2.78mJ

Ans:B

[13] The current carrying capacity of a 1W, 4MΩ resistor used in radio receiver is 
(a) 0.5kA
(b) 2kA
(c) 2mA
(d) 0.5mA

Ans: D

 
[14] A capacitor is charged by a constant current of 2mA and results in a voltage increase of 12V in a 10 sec interval. The value of capacitance is
(a) 0.75mF
(b) 1.33mF
(c) 0.6mF
(d) 1.67mF

Ans: D

[15] Three phase ac supply

A.  Has sawtooth waves that add together in phase

B.  Consists of three sine waves in different phases

C.  Is a sine wave with exactly three harmonics

D.  Is of interest only to physicists

Ans: B