D.c. Generators MCQs

Option A: commutator

Option B: solid connection

Option C: slip rings

Option D: none of above

Correct Answer: commutator ✔

Option A: speed

Option B: load

Option C: voltage

Option D: speed and voltage

Correct Answer: load ✔

Option A: speed

Option B: load

Option C: voltage

Option D: speed and voltage

Correct Answer: load ✔

Option A: reduce the bulk

Option B: provide the bulk

Option C: insulate the core

Option D: reduce eddy current loss

Correct Answer: reduce eddy current loss ✔

Option A: case iron

Option B: carbon

Option C: silicon steel

Option D: stainless steel

Correct Answer: silicon steel ✔

Option A: 0.005 mm

Option B: 0.05 mm

Option C: 0.5 m

Option D: 5 m

Correct Answer: 0.5 m ✔

Option A: copper lugs

Option B: resistance wires

Option C: insulation pads

Option D: brazing

Correct Answer: copper lugs ✔

Option A: length of conductor

Option B: cross-sectional area of the conductor

Option C: number of conductors

Option D: all of the above

Correct Answer: all of the above ✔

Option A: mica

Option B: copper

Option C: cast iron

Option D: carbon

Correct Answer: copper ✔

Option A: copper is harder than mica

Option B: mica and copper are equally hard

Option C: mica is harder than copper

Option D: none of the above

Correct Answer: mica is harder than copper ✔

Option A: motion of conductor

Option B: lines of force

Option C: either of the above

Option D: none of the above

Correct Answer: lines of force ✔

Option A: direction of induced e.m.f.

Option B: direction of flux

Option C: direction of motion of the conductor if forefinger points in the direction of generated e.m.f.

Option D: direction of motion of conductor, if forefinger points along the lines of flux

Correct Answer: direction of motion of conductor, if forefinger points along the lines of flux ✔

Option A: rivets

Option B: counter sunk screws

Option C: brazing

Option D: welding

Correct Answer: counter sunk screws ✔

Option A: magnetic flux, direction of current flow and resultant force

Option B: magnetic flux, direction of motion and the direction of e.m.f. induced

Option C: magnetic field strength, induced voltage and current

Option D: magnetic flux, direction of force and direction of motion of conductor

Correct Answer: magnetic flux, direction of motion and the direction of e.m.f. induced ✔

Option A: current

Option B: voltage

Option C: speed

Option D: none of above

Correct Answer: speed ✔

Option A: where low voltage and high currents are involved

Option B: where high voltage and small cur-rents are involved

Option C: in both of the above cases

Option D: in none of the above cases

Correct Answer: where low voltage and high currents are involved ✔

Option A: Lap winding

Option B: Wave winding

Option C: Either of A. and B. above

Option D: Depends on other features of design

Correct Answer: Wave winding ✔

Option A: severe sparking

Option B: rough commutator surface

Option C: imperfect contact

Option D: any of the above

Correct Answer: any of the above ✔

Option A: ball bearings

Option B: bush bearings

Option C: magnetic bearmgs

Option D: needle bearings

Correct Answer: ball bearings ✔

Option A: double the number of poles

Option B: same as the number of poles

Option C: half the number of poles

Option D: two

Correct Answer: same as the number of poles ✔

Option A: all the four poles are north poles

Option B: alternate poles are north and south

Option C: all the four poles are south poles

Option D: two north poles follow two south poles

Correct Answer: alternate poles are north and south ✔

Option A: is amenable to better voltage control

Option B: is more stable

Option C: has exciting current independent of load current

Option D: has all above features

Correct Answer: has all above features ✔