Rectifiers MCQs | Rectifiers Multiple Choice Questions and Answers

Questions
1 Which of the following isn’t a type of rectifier?
A Precision Half-wave Rectifier
B Bridge Rectifier
C Peak Rectifier
D None of the mentioned

Answer: None of the mentioned
2 For a half-wave rectifier having diode voltage VD and supply input of VI, the diode conducts for π – 2Θ, where Θ is given by
A tan -1 VD/VI
B tan-1 VD/VI – VI
C sin-1 VD/VI
D sin-1 VD/VI – VI

Answer: sin-1 VD/VI

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3 The diode rectifier works well enough if the supply voltage is much than greater than 0.7V. For smaller voltage (of few hundreds of millivolt) input which of the following can be used?
A Superdiode
B Peak rectifier
C Precision rectifier
D None of the mentioned

Answer: Superdiode
4 A simple diode rectifier has ‘ripples’ in the output wave which makes it unsuitable as a DC source. To overcome this one can use
A A capacitor in series with a the load resistance
B A capacitor in parallel to the load resistance
C Both of the mentioned situations will work
D None of the mentioned situations will work

Answer: A capacitor in parallel to the load resistance
5 In mercury arc rectifier positive ions are attracted towards
A Anode
B Cathode
C Shell bottom
D Mercury pool

Answer: Cathode
6 The internal efficiency of a mercury arc rectifier depends on
A Voltage only
B Current only
C R.M.S. value of current
D Voltage and current

Answer: Voltage only
7 The voltage drop at anode, in a mercury arc rectifier is due to
A Self restoring property of mercury
B High ionization potential
C Energy spent in overcoming the electrostatic field
D High temperature inside the rectifier

Answer: Energy spent in overcoming the electrostatic field
8 Mercury, in arc rectifiers, is chosen for cathode because
A It's ionization potential is relatively low
B Its atomic weight is quite high
C Its boiling point and specific heat are low
D All of the above

Answer: All of the above
9 The cathode voltage drop in a mercury arc rectifier is due to
A Expenditure of energy in ionization
B Surface resistance
C Expenditure of energy in over-coming the electrostatic field
D Expenditure of energy in liberating electrons from the mercury

Answer: Expenditure of energy in liberating electrons from the mercury
10 If cathode and anode connections in a mercury arc rectifier are interchanged
A The rectifier will not operate
B Internal losses will be reduced
C Both ion and electron streams will move in the same direction
D The rectifier will operate at reduced efficiency

Answer: The rectifier will not operate
11 In a three-phase mercury arc rectifier anode conducts for
A One third of a cycle
B One fourth of a cycle
C One half of a cycle
D Two third of a cycle

Answer: One third of a cycle
12 Which of the following is the loss within the mercury arc rectifier chamber?
A Voltage drop in arc
B Voltage drop at the anode
C Voltage drop at the cathode
D All of the above

Answer: All of the above
13 A commuting rectifier consists of commutator driven by
A An induction motor
B A synchronous motor
C A D.C. series motor
D A D.C. shunt motor

Answer: A synchronous motor
14 The efficiency of the copper oxide rectifier exceeds
A 90 to 95%
B 85 to 90%
C 70 to 80%
D 65 to 75%

Answer: 65 to 75%
15 The efficiency of an electrolytic rectifier is nearly
A 80%
B 70%
C 60%
D 40%

Answer: 60%
16 Which of the following mercury arc rectifier will deliver least undulating current?
A Six phase
B Three phase
C Two phase
D Single phase

Answer: Six phase
17 In a mercury arc rectifier characteristic blue luminosity is due to
A Colour of mercury
B Ionization
C High-temperature
D Electron streams

Answer: Ionization
18 In a mercury arc rectifier.............flow from anode to cathode
A Ions
B Electrons
C Ions and electrons
D Any of the above

Answer: Ions
19 A mercury arc rectifier possesses ...............regulation characteristics
A Straight line
B Curved line
C Exponential
D All of the alarms

Answer: Straight line
20 The potential drop in the arc in a mercury arc rectifier varies
A 0.05 to 0.2 V per cm length of the arc
B 0.5 to 1.5 V per cm length of the arc
C 2 V to 3.5 V per cm length of the arc
D None of the above

Answer: None of the above
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