A. copper is harder than mica
B. mica and copper are equally hard
C. mica is harder than copper
D. none of the above
Related Mcqs:
- In D.C. generators the pole shoes are fastened to the pole core by_____________?
A. rivets
B. counter sunk screws
C. brazing
D. welding - Brushes of D.C. machines are made of_________?
A. carbon
B. soft copper
C. hard copper
D. all of above - If brushes of a D.C. generator are moved in order to bring these brushes in magnetic neutral axis, there will be________________?
A. demagnetisation only
B. cross magnetisation as well as mag¬netisation
C. crossmagnetisation as well as demagnetising
D. cross magnetisation only - To achieve sparkless commutation brushes of a D.C. generator are rockedm ahead so as to bring them?
A. just ahead of magnetic neutral axis
B. in magnetic neutral axis
C. just behind the magnetic neutral axis
D. none - A D.C. generator can be considered as____________?
A. rectifier
B. primemover
C. rotating amplifier
D. power pump - Two generators A and B have 6-poles each. Generator A has wave wound armature while generator B has lap wound armature. The ratio of the induced e.m.f. is generator A and B will be_______________?
A. 2 : 3
B. 3 : 1
C. 3 : 2
D. 1 : 3 - In over compounded generator, full load terminal voltage is______________?
A. almost zero
B. less than no load terminal voltage
C. more than no load terminal voltage
D. equal to no-load terminal voltage - A shunt generator running at 1000 r.p.m. has generated e.m.f. as 200 V. If the speed increases to 1200 r.p.m., the generated e.m.f. will be nearly_______________?
A. 150 V
B. 175 V
C. 240 V
D. 290 V - In a separately excited generator supplying rated load the armature reaction.
A. is always present
B. is always absent
C. may be sometimes present
D. none of the above - In a D.C. generator the critical resistance can be increased by_____________?
A. increasing its field resistance
B. decreasing its field resistance
C. increasing its speed
D. decreasing its speed
