Rectifiers And Converters MCQs

Option A: Rectifiers

Option B: Motor converters

Option C: Motor-generator sets

Option D: Rotary converters

Correct Answer: All of the above ✔

Option A: by means of a small auxiliary motor

Option B: from AC. side as induction motor

Option C: from D.C. side as D.C. motor

Option D: any of the above methods

Correct Answer: any of the above methods ✔

Option A: Battery charging work

Option B: Arc welding

Option C: Electrolytic and electro-chemical processes

Option D: Arc lamps for search lights

Correct Answer: All of the above ✔

Option A: two

Option B: three

Option C: four

Option D: six

Correct Answer: two ✔

Option A: an induction motor and a D.C. generator

Option B: a synchronous motor and a D.C. generator

Option C: a D.C. series motor and a D.C. generator

Option D: none of the above

Correct Answer: B. a synchronous motor and a D.C. generator ✔

Option A: 200-100 V

Option B: 600—800 V

Option C: 1000—1200 V

Option D: 1700—2000 V

Correct Answer: 1700—2000 V ✔

Option A: Motor generator set

Option B: Motor converter

Option C: Rotary converter

Option D: Any of the above

Correct Answer: Rotary converter ✔

Option A: one armature and one field

Option B: two armatures and one field

Option C: one armature and two fields

Option D: none of the above

Correct Answer: one armature and one field ✔

Option A: a transformer

Option B: an induction motor

Option C: an alternator

Option D: any D.C. machine

Correct Answer: D. any D.C. machine ✔

Option A: Load

Option B: Aluminium

Option C: Copper

Option D: Zinc

Correct Answer: Aluminium ✔

Option A: Motor-generator set

Option B: Motor converter

Option C: Rotary converter

Option D: Mercury arc rectifier

Correct Answer: Mercury arc rectifier ✔

Option A: low power factor

Option B: high power factor

Option C: zero power factor

Option D: none of the above

Correct Answer: high power factor ✔

A. d.c. only
B. a.c. only
C. partly a.c. and partly d.c.

Correct Answer: partly a.c. and partly d.c. ✔

Option A: Illumination

Option B: Electrolysis

Option C: Variable speed operation

Option D: Traction

Correct Answer: Electrolysis ✔

Option A: anode

Option B: cathode

Option C: shell bottom

Option D: mercury pool

Correct Answer: cathode ✔

Option A: Telephones

Option B: Relays

Option C: Time switches

Option D: All of the above

Correct Answer: All of the above ✔

Option A: Synchronous motor

Option B: Squirrel cage induction motor

Option C: Slip ring induction motor

Option D: Any of the above

Correct Answer: Synchronous motor ✔

Option A: same

Option B: less

Option C: double

Option D: three times

Correct Answer: less ✔

Option A: 0.05 V to 0.2 V per cm length of the arc

Option B: 0.5 V to 1.5 V per cm length of the arc

Option C: 2 V to 3.5 V per cm length of the arc

Option D: none of the above

Correct Answer: 2 V to 3.5 V per cm length of the arc ✔

Option A: its ionization potential is relatively low

Option B: its atomic weight is quite high

Option C: its boiling point and specific heat are low

Option D: it remains in liquid state at ordi¬nary temperature

Correct Answer: all of the above ✔

Option A: 100 A at 100 V

Option B: 200 A at 200 V

Option C: 300 A at 300 V

Option D: 400 A at 400 V

Correct Answer: 500 A at 500 V ✔

Option A: expenditure of energy in ionization

Option B: surface resistance

Option C: expenditure of energy in overcoming the electrostatic field

Option D: expenditure of energy in liberating electrons from the mercury

Correct Answer: expenditure of energy in liberating electrons from the mercury ✔

Option A: anode is heated

Option B: tube is evacuated

Option C: an auxiliary electrode is used

Option D: low mercury vapour pressures are used

Correct Answer: an auxiliary electrode is used ✔

Option A: it is light in weight and occupies small floor space

Option B: it has high efficiency

Option C: it has high overload capacity

Option D: it is comparatively noiseless

Correct Answer: all of the above ✔

Option A: voltage only

Option B: current only

Option C: voltage and current

Option D: r.m.s. value of current

Correct Answer: voltage only ✔

Option A: is directly proportional to load

Option B: is inversely proportional to load

Option C: varies exponentially with the load current

Option D: is almost independent of load current

Correct Answer: is almost independent of load current ✔

Option A: the rectifier will not operate

Option B: internal losses will be reduced

Option C: both ion and electron streams will move in the same direction

Option D: the rectifier will operate at reduced efficiency

Correct Answer: the rectifier will not operate ✔

Option A: self restoring property of mercury

Option B: high ionization potential

Option C: energy spent in overcoming the electrostatic field

Option D: high temperature inside the rectifier

Correct Answer: energy spent in overcoming the electrostatic field ✔

Option A: anode drop and cathode drop

Option B: anode drop and arc drop

Option C: cathode drop and arc drop

Option D: anode drop, cathode drop and arc drop

Correct Answer: cathode drop and arc drop ✔

Option A: 5.4 V

Option B: 8.4 V

Option C: 10.4 V

Option D: 16.4 V

Correct Answer: 10.4 V ✔

Option A: 2000 A

Option B: 1500 A

Option C: 1000 A

Option D: 500 A

Correct Answer: 500 A ✔

Option A: colour of mercury

Option B: ionization

Option C: high temperature

Option D: electron streams

Correct Answer: ionization ✔

Option A: Voltage drop in transformer reactance

Option B: Voltage drop in resistance of transformer and smoothing chokes

Option C: Arc voltage drop

Option D: All of the above

Correct Answer: All of the above ✔

Option A: Six-phase

Option B: Three-phase

Option C: Two-phase

Option D: Single-phase

Correct Answer: Six-phase ✔

Option A: one-third of a cycle

Option B: one-fourth of a cycle

Option C: one-half a cycle

Option D: two-third of a cycle

Correct Answer: one-third of a cycle ✔

Option A: ions

Option B: electrons

Option C: ions and electrons

Option D: any of the above

Correct Answer: ions ✔

Option A: straight line

Option B: curved line

Option C: exponential

Option D: none of the above

Correct Answer: none of the above ✔

Option A: accelerates

Option B: decelerates

Option C: any of the above

Option D: none of the above

Correct Answer: accelerates ✔

Option A: The voltage regulation of the rec¬tifier should be low

Option B: In the output circuit there should be no harmonics

Option C: The power factor of the system should be high

Option D: The rectifier supply transformer should be utilized to the best ad-vantage

Correct Answer: all of the above ✔

Option A: resistance

Option B: capacitance

Option C: leakage reactance

Option D: any of the above

Correct Answer: leakage reactance ✔

Option A: shunt motor

Option B: synchronous motor

Option C: induction regulator

Option D: synchronous generator

Correct Answer: induction regulator ✔

Option A: maximum grid voltage

Option B: critical grid voltage

Option C: any of the above

Option D: none of the above

Correct Answer: critical grid voltage ✔

Option A: Copper oxide rectifier is a linear device

Option B: Copper oxide rectifier is not a perfect rectifier

Option C: Copper oxide rectifier has a low efficiency

Option D: Copper oxide rectifier finds use in control circuits

Correct Answer: Copper oxide rectifier is a linear device ✔

Option A: magnitude

Option B: polarity

Option C: phase

Option D: any of the above

Correct Answer: phase ✔

Option A: They are mechanically strong

Option B: They do not require any voltage for filament heating

Option C: Both (A) and (B)

Option D: None of the above

Correct Answer: Both (A) and (B) ✔

Option A: 10°C

Option B: 20°C

Option C: 30°C

Option D: 45°C

Correct Answer: 45°C ✔

Option A: 5 to 10 per cent

Option B: 15 to 20 per cent

Option C: 25 to 30 per cent

Option D: none of the above

Correct Answer: 5 to 10 per cent ✔

Option A: 90 to 95%

Option B: 85 to 90%

Option C: 80 to 85%

Option D: 65 to 75%

Correct Answer: 65 to 75% ✔

Option A: 25°C

Option B: 40°C

Option C: 60°C

Option D: 75°C

Correct Answer: 75°C ✔

Option A: 10 V

Option B: 30 V

Option C: 60 V

Option D: 100 V

Correct Answer: 100 V ✔

Option A: 25, 35

Option B: 40, 50

Option C: 60, 70

Option D: 75, 85

Correct Answer: 75, 85 ✔

Option A: an induction motor

Option B: a synchronous motor

Option C: a D.C. series motor

Option D: a D.C. shunt motor

Correct Answer: a synchronous motor ✔

Option A: copper

Option B: aluminium

Option C: silver

Option D: graphite

Correct Answer: graphite ✔

Option A: Copper oxide rectifiers

Option B: Selenium rectifiers

Option C: Mercury arc rectifiers

Option D: Mechanical rectifiers

Correct Answer: Selenium rectifiers ✔

Option A: Voltage drop in arc

Option B: Voltage drop at the anode

Option C: Voltage drop at the cathode

Option D: All of the above

Correct Answer: All of the above ✔

Option A: Mechanical rectifiers

Option B: Copper oxide rectifiers

Option C: Selenium rectifiers

Option D: Electrolytic rectifiers

Correct Answer: Electrolytic rectifiers ✔

Option A: 80%

Option B: 70%

Option C: 60%

Option D: 40%

Correct Answer: 60% ✔

Option A: graphite

Option B: boron carbide

Option C: aluminium

Option D: copper

Correct Answer: boron carbide ✔