Electrical Engineering Mcqs Practice Test

Question 1

In case the air gap in an induction motor is increased?

Accepted Answer

B. the power factor will decrease

Question 2

In an induction motor, no-load the slip is generally____________?

Accepted Answer

A. less than 1%

Question 3

The shaft of an induction motor is made of_____________?

Accepted Answer

C. carbon steel

Question 4

The torque of an induction motor is___________?

Accepted Answer

A. directly proportional to slip

Question 5

The frame of an induction motor is usually made of____________?

Accepted Answer

B. cast iron

Question 6

A series generator can self-excite:______________?

Accepted Answer

B. only if the load current is not zero

Question 7

A D.C. generator works on the principle of____________?

Accepted Answer

C. Faraday’s law of electromagnetic induction

Question 8

The open circuit voltage of a compound generator is 250 V. At full load the terminal voltage____________?

Accepted Answer

C. may be greater or less than 250 V

Question 9

The terminal voltage of a series generator is 150 V when the load current is 5 A. If the load current is increased to 10 A, the terminal voltage will be____________?

Accepted Answer

C. greater than 150 V

Question 10

A shunt generator can self-excite:_________________?

Accepted Answer

A. only if the resistance of the field circuit is less than critical value

Question 11

With a D.C. generator which of the following regulation is preferred ?

Accepted Answer

D. 1% regulation

Question 12

Two D.C. shunt generators, each with armature resistance of 0.02 ohm and field resistance of 50 ohm run in parallel and supply a total current of 1000 amperes to the load circuit. If their e.m.fs. are 270 V and 265 V, their bus bar voltage will be_____________________?

Accepted Answer

B. 267.5 V

Question 13

The essential condition for parallel operation of two D.C. generators is that they have ________________?

Accepted Answer

C. the same drooping voltage characteristics

Question 14

When two D.C. generators are running in parallel an equilizer bar is used______________?

Accepted Answer

D. so that the two identical machines will pass approximately equal cur¬rents to the load

Question 15

Two generators are running in parallel. One of the generators may run as motor for which of the following reasons ?

Accepted Answer

D. That generator takes large share of loads

Question 16

Which of the following generators will be preferred if they are required to be run in parallel?

Accepted Answer

A. Shunt generators

Question 17

Which of the following generating machine will offer constant voltage on all loads?

Accepted Answer

C. Level compounded generator

Question 18

If a self excited D.C. generator after being installed, fails to build up on its first trial run, the first thing to do is to______________?

Accepted Answer

A. reverse the field connections

Question 19

The main factor which leads to unstable parallel operation of flat and over compounded generators is_____________?

Accepted Answer

A. their rising voltage characteristics

Question 20

When two D.C. series generators are running in parallel, an equilizer bar is used________________?

Accepted Answer

C. so that two similar machines will pass approximately equal currents to the load