## electrician

### MCQ ON DC GENERATOR PAGE - 1

1.
 If the axis of a moving coil is kept parallel to the flux then the E.M.F induced in the coil will be A Minimum B Maximum C Nil D One volt Answer : C Explanation :
2.
 By rotating a conductor in a magnetic field, the induced E.M.F will be A Static B Dynamic C Induced E.M.F D None of the above Answer : B Explanation :
3.
 For inducing an emf of 1 volt in 1 second time, a conductor will have to cut: A 10 Maxwell lines B 108 lines C 1 weber magnetic flux D None of the above Answer : C Explanation :
4.
 On doubling the supply frequency, the eddy current will: A Become half of their former value B Become four times of their former value C Remain unaffected D Become eight time of their former value Answer : B Explanation :
5.
 In order to reduce hysteresis losses, the cores of electrical machines are generally made of A Tungsten steel B Caste iron C High carbon steel D Silicon steel Answer : D Explanation :
6.
 Which of the following statement is incorrect? A Whenever the flux linking through a coil or a circuit changes, E.M.F is produced B The direction of dynamically induced E.M.F can be determined by applying Fleming’s  ri C Coefficient of coupling for tightly coupled coils is zero D The coefficient of self-inductance its proportional to the square of the number of turns on it. Answer : C Explanation :
7.
 Whenever a conductor cuts magnetic flux, an emf is induced in the same. The statement refers to A Joule’s law B Coulomb’s law C Faraday’s law D Lenz’s law Answer : C Explanation :
8.
 The given figure shows a coil with a closed iron core what do the dotted lines represent? A Magnetic potential B Magnetomotive force C Magnetic field strength D Magnetic flux Answer : D Explanation :
9.
 The magnetic flux shown in above fig. can be increased by A Increasing the magneto motive force B Decreasing the magneto motive force C Reversing the direction of current D Making an air-gap in the core Answer : A Explanation :
10.
 The law which states that the induced a emf and current always opposes the cause producing it was presented by A Lenz B Faraday C Maxwell D Ohm Answer : A Explanation :
11.
 Degaussing is the process of A Removing gases from a material B Removing impurities from magnetic materials C Demagnetizing a metallic part D Demagnetizing a magnet Answer : C Explanation :
12.
 An open circuit curve is drawn between A E and IF B N and IL C E and IA D E0 and IF (Where E0 =no load current, N=no. of armature conduc Answer : D Explanation :
13.
 In a level compound generator, full load voltage is found to be _____the terminal voltage A Lesser than B Higher than C Equal to D Much lesser than Answer : C Explanation :
14.
 In which type of d.c. machine poles is residual magnetism necessary A Shunt generator B Motor C Separately excited generator D Permanent magnet type generator Answer : A Explanation :
15.
 Armature cores are commonly made of A Iron B Silicon steel C High carbon steel D Stainless steel Answer : B Explanation :
16.
 Lap winding has____ parallel paths A Two B Four C Equal to the no of poles D One Answer : C Explanation :
17.
 The output voltage of a single loop generator is a A Steady d.c. B Steady ac C Pulsating ac D Pulsating dc Answer : D Explanation :
18.
 What effect on the current flow takes plane on reversing the direction of movement of a conductor in the magnetic field of a generator A No effect takes place B Current flow is stopped C The direction of current flow is reversed D The magnitude of current flow is decreased Answer : C Explanation :
19.
 In most generators the output voltage is induced by A Rotating magnetic filed past stationary coils B Relative motion between eh field and the armature coils C Converting electrical energy into mechanical energy D Rotating the coils around a magnetic filed Answer : B Explanation :
20.
 The shunt field of a compound generator is connected across both the series field and the armature. The connection is known as A Long shunt B Short shunt C Differential compound D Cumulative compound Answer : A Explanation :
21.
 Generators are run in parallel for achieving the advantage of : A High reliability B High efficiency C Meeting higher load demands D All the above Answer : D Explanation :