Electrical MCQ Question and Answer
Electrical MCQ Question and Answer
11. Chopper circuits are used to control the speed of dc motors which are fed from fixed dc voltage sources. Variables voltage output can be obtained by which of the following methods?
1. Varying the “on” to “off’ time ratio
2. Adjusting the wave shape
3. Adjusting the frequency of switching
4. Using a saturable reactor in series with the motor
Select the correct answer using the codes given below:
Codes:
1. Varying the “on” to “off’ time ratio
2. Adjusting the wave shape
3. Adjusting the frequency of switching
4. Using a saturable reactor in series with the motor
Select the correct answer using the codes given below:
Codes:
- l and 2
- 1 and 3
- 2 and 3
- 2 and 4
12. Match List I with List II and select the correct answer using the codes given below the lists:
List I
A. Rolling mill drive
B. Power drill drive
C. Hoist drive
List II
1. Adjustable speed drive
2. Variable speed drive
3. Constant speed drive
Codes:
A B C
List I
A. Rolling mill drive
B. Power drill drive
C. Hoist drive
List II
1. Adjustable speed drive
2. Variable speed drive
3. Constant speed drive
Codes:
A B C
- 1 2 3
- 2 3 1
- 3 1 2
- 1 2 1
13. The incremental cost characteristics of the two units in a plant are given by:
IC1 = Rs (0.1P1 + 8.0) per MWh
IC2 Rs (0.15P2 +3.0) per MWh
The optimum sharing of load when the total load is l00 MW is
IC1 = Rs (0.1P1 + 8.0) per MWh
IC2 Rs (0.15P2 +3.0) per MWh
The optimum sharing of load when the total load is l00 MW is
- P1= 6OMW and P2 = 4OMW
- P1 = 33.3 MW and P2 = 66.7 MW
- P1 40 MW and P2 60 MW
- P1 = 66.7 MW and P2 = 33.3 MW
14. Match List I with List II and select the correct answer using the codes given below the lists:
List I
(Type of cables)
A. Polyvinyl chloride
B. Paper impregnated
C. Cross-linked polyethylene
List II
(Dielectric constant of insulation)
1. 2.35
2. 3.8
3. 6.0
Codes:
A B C
List I
(Type of cables)
A. Polyvinyl chloride
B. Paper impregnated
C. Cross-linked polyethylene
List II
(Dielectric constant of insulation)
1. 2.35
2. 3.8
3. 6.0
Codes:
A B C
- 1 2 3
- 2 3 1
- 3 1 2
- 3 2 1
15. Which of the following are the specific features that apply to a current source inverter?
1. Capacity to feed several motors simultaneously.
2. Capacity to provide straightforward regeneration.
3. Inherent protection in case there is a load short-circuits.
Select the correct answer using the codes given below:
Codes:
1. Capacity to feed several motors simultaneously.
2. Capacity to provide straightforward regeneration.
3. Inherent protection in case there is a load short-circuits.
Select the correct answer using the codes given below:
Codes:
- 1, 2 and 3
- 1 and 2
- 1 and 3
- 2 and 3
16. Consider the following statements:
A free wheeling diode across the load circuit of a two-pulse converter
1. Improves the operating power factor.
2. Makes the distortion factor (I1 / I)vary as a function of firing angle
3. is effective in reducing the smoothing inductance.
4. Distorts the line current
Of these statements:
A free wheeling diode across the load circuit of a two-pulse converter
1. Improves the operating power factor.
2. Makes the distortion factor (I1 / I)vary as a function of firing angle
3. is effective in reducing the smoothing inductance.
4. Distorts the line current
Of these statements:
- 1, 3 and 4 are correct
- 1, 2 and 3 are correct
- 1, 2 and 4 are correct
- 2, 3 and 4 are correct
17. Which of the following gates corresponds to the truth table given below?
A B Output
1 1 0
0 1 1
1 0 1
0 0 1
A B Output
1 1 0
0 1 1
1 0 1
0 0 1
- NAND
- OR
- AND
- XOR