AP Mocktest 2020-3

1. The direction of rotation of a DC motor can be determined by _______

A. Flemings right hand rule
B. Flemings left hand rule
C. Lenz's law
D. Ampere law

Answer : B. Flemings left hand rule
Explanation:-

2. An ideal amplifier has _____

A. positive feedback
B. uniform frequency response
C. infinite voltage gain
D. responds only to signals at its inout terminals

Answer : D. responds only to signals at its inout terminals
Explanation:-

3. Transmission lines are transposed to ______

A. reduce corona loss
B. reduce skin effect
C. prevent interference with neighboring telephone lines
D. prevent short circuit between any two lines

Answer : C. prevent interference with neighboring telephone lines
Explanation:-

4. The TRIAC is equivalent to _______

A. Two SCRS connected in parallel
B. Two SCRs connected in antiparallel
C. One SCR, one diode connected in parallel
D. One diode, one SCR connected in antiparallel

Answer : B. Two SCRs connected in antiparallel
Explanation:-

5. For a medium length transmission line, A is ______

A. equal to B
B. equal to C
C. equal to D
D. not equal to B,C,D

Answer : C. equal to D
Explanation:-

6. The transformer efficiency at relatively light loads is quite low. This is due to _____

A. small copper losses
B. small secondary output
C. High fixed loss in comparision to the output
D. Poor power factor

Answer : C. High fixed loss in comparision to the output
Explanation:-

7. In order to reduce the hysterisis loss _____

A. Core may be laminated
B. silicon steel may be used as the core material
C. core may be constructed with any permanent magnet material such as Alnico
D. core may be impregnated with varnish

Answer : B. silicon steel may be used as the core material
Explanation:- Silicon steel has low reluctance

8. The sag of a transmission line is least affected owing to ______

A. weight of the conductor
B. current through the conductor
C. atmospheric temperature
D. ice deposition on the conductor

Answer : B. current through the conductor
Explanation:-

9. Threshold characteristics of a plain impedance relay in a complex Z plane is a ______

A. circle passing through origin
B. circle with the centre at the origin
C. straight line passing through the origin
D. straight line offset from the origin

Answer : B. circle with the centre at the origin
Explanation:-

10. Free running and coasting periods are generally long in case of ________

A. city service
B. suburban service
C. main line service
D. outer suburban service

Answer : C. main line service
Explanation:-