In a three-phase mercury arc rectifiers each anode conducts for____________?

A. One-third of a cycle
B. One-fourth of a cycle
C. One-half a cycle
D. Two-third of a cycle

In a mercury arc rectifier________ flow from anode to cathode

A. Ions
B. Electrons
C. Ions and electrons
D. Any of the above

A mercury arc rectifier possesses __________ regulation characteristics

A. Straight line
B. Curved line
C. Exponential
D. None of the above

In a grid control of mercury arc rectifiers when the grid is made positive relative to cathode, then it the electrons on their may to anode.

A. Accelerates
B. Decelerates
C. Any of the above
D. None of the above

On which of the following factors the number of phases for which a rectifier should be designed depend ?

A. the voltage regulation of the rec¬tifier should be low
B. in the output circuit there should be no harmonics
C. the power factor of the system should be high
D. the rectifier supply transformer should be utilized to the best ad-vantage

It is the_________of the transformer on which the magnitude of angle of overlap depends?

A. Resistance
B. Capacitance
C. Leakage reactance
D. Any of the above

In a phase-shift control method, the phase shift between anode and grid voltages can be achieved by means of______________?

A. Shunt motor
B. Synchronous motor
C. Induction regulator
D. Synchronous generator

In mercury arc rectifiers having grid, the arc can be struck between anode and cathode only when the grid attains a certain potential, this potential being known as______________?

A. Maximum grid voltage
B. Critical grid voltage
C. Any of the above
D. None of the above

Which of the following statement is incorrect ?

A. Copper oxide rectifier is a linear device
B. Copper oxide rectifier is not a perfect rectifier
C. Copper oxide rectifier has a low efficiency
D. Copper oxide rectifier finds use in control circuits

In phase-shift control method the control is carried out by varying the of grid voltage

A. Magnitude
B. Polarity
C. Phase
D. Any of the above