Question: In a mercury arc rectifier________ flow from anode to cathode.

• 1. ions
• 2. electrons
• 3. ions and electrons
• 4. any of the above

Question: A mercury arc rectifier possesses __________ regulation characteristics.

• 1. straight line
• 2. curved line
• 3. exponential
• 4. none of the above

Question: 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.

• 1. accelerates
• 2. decelerates
• 3. any of the above
• 4. none of the above

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

• 1. The voltage regulation of the rec¬tifier should be low
• 2. In the output circuit there should be no harmonics
• 3. The power factor of the system should be high
• 4. all of the above

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

• 1. resistance
• 2. capacitance
• 3. leakage reactance
• 4. any of the above

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

• 1. shunt motor
• 2. synchronous motor
• 3. induction regulator
• 4. synchronous generator

Question: 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______________?

• 1. maximum grid voltage
• 2. critical grid voltage
• 3. any of the above
• 4. none of the above

Question: Which of the following statement is incorrect ?

• 1. Copper oxide rectifier is a linear device
• 2. Copper oxide rectifier is not a perfect rectifier
• 3. Copper oxide rectifier has a low efficiency
• 4. Copper oxide rectifier finds use in control circuits

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

• 1. magnitude
• 2. polarity
• 3. phase
• 4. any of the above

Question: The metal rectifiers are preferred to valve rectifiers due to which of the following advantages ?

• 1. They are mechanically strong
• 2. They do not require any voltage for filament heating
• 3. Both (A) and (B)
• 4. None of the above