AP ECET EEE 2017-7

1. In a HVDC System

A. both generation and distribution is DC
B. Generation is AC and distribution is DC
C. Generation is DC and distribution is AC
D. both generation and distribution is AC

Answer : Generation is AC and distribution is DC
Explain:-

2. Disruptive corona begins in smooth cylindrical conductors in air at NTP if the electric field intensity at the conductor surface goes up to

A. 21.1 KV(RMS)/cm
B. 21.1 KV(peak)/cm
C. 21.1 KV(average)/cm
D. 21.1 V(RMS)/cm

Answer : 21.1 KV(RMS)/cm
Explain:-

3. In a short transmission line, voltage regulation is zero when the power factor angle of the load at the receiving end side is equal to

A. tan-1 (X/R)
B. tan-1 (R/X)
C. tan-1 (X/Z)
D. tan-1 (R/Z)

Answer : tan-1 (R/X)
Explain:-

4. Long distance railways use which of the following

A. 200V DC
B. 25 kV Single phase AC
C. 25 kV three phase AC
D. 25 kV two phase AC

Answer : 25 kV Single phase AC
Explain:-

5. Quadrilateral speed-time curve pertains to which of the following services

A. Main line service
B. Urban service
C. Sub-urban service
D. Urban and Sub-urban service

Answer : Urban and Sub-urban service
Explain:-

6. In case of___________free running and coasting periods are generally long

A. Main line service
B. Urban service
C. Sub-urban service
D. Urban and Sub-urban service

Answer : Main line service
Explain:-

7. The voltage used for suburban trains in DC system is usually

A. 12V
B. 24V
C. 220V
D. 600 to 750V

Answer : 600 to 750V
Explain:-

8. Which of the following will not decrease as a result of introduction of negative feedback

A. Instability
B. Bandwidth
C. Overall gain
D. Distortion

Answer : Bandwidth
Explain:-

9. In a closed loop control system

A. Control action is independent of the output
B. Output is independent of input
C. There is no feedback
D. Control action is dependent on the output

Answer : Control action is independent of the output
Explain:-

10. The effect of integral control on the steady state error and that on the relative stability of the system is

A. Both are increased
B. steady state error is increased but Relative stability is reduced
C. steady state error is reduced but Relative stability is increased
D. both are reduced

Answer : both are reduced
Explain:-