Electrical Engineering Mcqs Practice Test

Question 1

In a mercury arc rectifier positive ions are attracted towards______________?

Accepted Answer

B. cathode

Question 2

In which of the following equipment direct current is needed ?

Accepted Answer

D. All of the above

Question 3

Which of the following AC. motors is usually used in large motor-generator sets?

Accepted Answer

A. Synchronous motor

Question 4

In a rotary converter I2R losses as compared to a D.C. generator of the same size will be___________?

Accepted Answer

B. less

Question 5

The potential drop in the arc, in a mercury arc rectifier, varies_____________?

Accepted Answer

C. 2 V to 3.5 V per cm length of the arc

Question 6

Mercury, in arc rectifiers, is chosen for cathode because________________?

Accepted Answer

E. all of the above

Question 7

Glass rectifiers are usually made into units capable of D.C. output (maximum continuous rating) of _____________?

Accepted Answer

E. 500 A at 500 V

Question 8

The cathdde voltage drop, in a mercury arc rectifier, is due to_____________?

Accepted Answer

D. expenditure of energy in liberating electrons from the mercury

Question 9

To produce cathode spot in a mercury arc rectifier______________?

Accepted Answer

C. an auxiliary electrode is used

Question 10

The advantage of mercury arc rectifier is that________________?

Accepted Answer

E. all of the above

Question 11

The internal efficiency of a mercury arc rectifier depends on___________?

Accepted Answer

A. voltage only

Question 12

In a mercury pool rectifier, the voltage drop across its electrodes___________?

Accepted Answer

D. is almost independent of load current

Question 13

If cathode and anode connections in a mercury arc rectifier are inter changed_____________?

Accepted Answer

A. the rectifier will not operate

Question 14

The voltage drop at anode, in a mercury arc rectifier is due to_____________?

Accepted Answer

C. energy spent in overcoming the electrostatic field

Question 15

The voltage drop between the anode and cathode, of a mercury arc rectifier comprises of the following_____________?

Accepted Answer

D. anode drop, cathode drop and arc drop

Question 16

The ionization potential of mercury is approximately_____________?

Accepted Answer

C. 10.4 V

Question 17

In a glass bulb mercury arc rectifier the maximum current rating is restricted to___________?

Accepted Answer

D. 500 A

Question 18

In a mercury arc rectifier characteristic blue luminosity is due to_____________?

Accepted Answer

B. ionization

Question 19

When a rectifier is loaded which of the following voltage drops take place ?

Accepted Answer

D. All of the above

Question 20

Which of the following mercury arc rectifier will deliver least undulating current?

Accepted Answer

A. Six-phase