Electrical Mock Test - Set 07
Today, all competitive exams are Multiple Choice Questions(MCQ) based examination system and the main factor is to answer each question in a prescribed time. So, practice as much as possible before the original test you are going to face.
Total number of Multiple Choice Question (MCQ) is 15 and time allotted for each question is 30 seconds. After the allotted time, the question will be marked as un-attempt.
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01. The following system is not generally used
(A) 1-phase 3-wire
(B) 1-phase 4-wire
(C) 3-phase 3-wire
(D) 3-phase 4-wire
Answer: Option A
02. On which of the following variables heat convection depends?
(A) Power density
(B) Temperature difference between heated surface and coolant
(C) Thermal resistivity, density, specific heat, Gravitational constant
(D) All of the above
Answer: Option D
03. In case of a reluctance motor, when the load is increased so that it cannot maintain synchronous speed the motor will
(A) Become unstable
(B) Draw excessive armature current and may burn out
(C) Fall out of synchronism and come to stand still
(D) Run as induction motor
Answer: Option D
04. If a third equal and similar charge is placed between two equal and similar charges, then this third charge will
(A) Move out of the field of influence of the two charges
(B) Remain in stable equilibrium
(C) Not be in equilibrium
(D) Be in unstable equilibrium
Answer: Option B
05. In any rotating machine that part which houses the conductors and in which e.m.f. induced is to be utilized is called
(A) Rotor
(B) Stator
(C) Field
(D) Armature
Answer: Option D
06. Which one of the following is not necessarily the advantage of D.C. motors over A.C. motors?
(A) Low cost
(B) Wide speed range
(C) Stability
(D) High starting torque
Answer: Option A
07. If the field circuit of an unloaded salient-pole synchronous motor gets suddenly open-circuited, then
(A) It runs at a slower speed
(B) The motor stops
(C) It continues to run at the same speed
(D) It runs at a very high speed
Answer: Option B
08. In a pure capacitive circuit if the supply frequency is reduced to 1/2, the current will
(A) Be reduced by half
(B) Be doubled
(C) Be four times at high
(D) Be reduced to one fourth
Answer: Option: A
09. The resistance of armature winding depends on
(A) Length of conductor
(B) Cross-sectional area of the conductor
(C) Number of conductors
(D) All of the above
Answer: Option D
10. The speed control of universal motor used for sewing machines is by
(A) Friction
(B) Varying the resistance
(C) Tapping the field
(D) Centrifugal mechanism
Answer: Option B
11. The cooling section in the surface condenser
(A) Increases the quantity of vapour extracted along with air
(B) Reduces the quantity of vapour extracted along with air
(C) Does not affect vapour quantity extracted but reduces pump capacity of air extraction pump
(D) None of the above
Answer: Option B
12. In a ∆-connected source feeding a Y-connected load
(A) Each phase voltage equals the difference of the corresponding load voltages
(B) Each phase voltage equals the corresponding load voltage
(C) Each phase voltage is one-third the corresponding load voltage
(D) Each phase voltage is 60° out of phase with the corresponding load voltage
Answer: Option A
13. Which one of the following is not the function of pole shoes in a D.C. machine?
(A) To reduce eddy current loss
(B) To support the field coils
(C) To spread out flux for better uniformity
(D) To reduce the reluctance of the magnetic path
Answer: Option A
14. Laminated cores, in electrical machines, are used to reduce
(A) Copper loss
(B) Eddy current loss
(C) Hysteresis loss
(D) All of the above
Answer: Option B
15. The magnetic reluctance of a material
(A) Decreases with increasing cross sectional area of material
(B) Increases with increasing cross-sectional area of material
(C) Does not vary with increasing cross-sectional area of material
(D) Any of the above
Answer: Option A
(A) 1-phase 3-wire
(B) 1-phase 4-wire
(C) 3-phase 3-wire
(D) 3-phase 4-wire
Answer: Option A
02. On which of the following variables heat convection depends?
(A) Power density
(B) Temperature difference between heated surface and coolant
(C) Thermal resistivity, density, specific heat, Gravitational constant
(D) All of the above
Answer: Option D
03. In case of a reluctance motor, when the load is increased so that it cannot maintain synchronous speed the motor will
(A) Become unstable
(B) Draw excessive armature current and may burn out
(C) Fall out of synchronism and come to stand still
(D) Run as induction motor
Answer: Option D
04. If a third equal and similar charge is placed between two equal and similar charges, then this third charge will
(A) Move out of the field of influence of the two charges
(B) Remain in stable equilibrium
(C) Not be in equilibrium
(D) Be in unstable equilibrium
Answer: Option B
05. In any rotating machine that part which houses the conductors and in which e.m.f. induced is to be utilized is called
(A) Rotor
(B) Stator
(C) Field
(D) Armature
Answer: Option D
06. Which one of the following is not necessarily the advantage of D.C. motors over A.C. motors?
(A) Low cost
(B) Wide speed range
(C) Stability
(D) High starting torque
Answer: Option A
07. If the field circuit of an unloaded salient-pole synchronous motor gets suddenly open-circuited, then
(A) It runs at a slower speed
(B) The motor stops
(C) It continues to run at the same speed
(D) It runs at a very high speed
Answer: Option B
08. In a pure capacitive circuit if the supply frequency is reduced to 1/2, the current will
(A) Be reduced by half
(B) Be doubled
(C) Be four times at high
(D) Be reduced to one fourth
Answer: Option: A
09. The resistance of armature winding depends on
(A) Length of conductor
(B) Cross-sectional area of the conductor
(C) Number of conductors
(D) All of the above
Answer: Option D
10. The speed control of universal motor used for sewing machines is by
(A) Friction
(B) Varying the resistance
(C) Tapping the field
(D) Centrifugal mechanism
Answer: Option B
11. The cooling section in the surface condenser
(A) Increases the quantity of vapour extracted along with air
(B) Reduces the quantity of vapour extracted along with air
(C) Does not affect vapour quantity extracted but reduces pump capacity of air extraction pump
(D) None of the above
Answer: Option B
12. In a ∆-connected source feeding a Y-connected load
(A) Each phase voltage equals the difference of the corresponding load voltages
(B) Each phase voltage equals the corresponding load voltage
(C) Each phase voltage is one-third the corresponding load voltage
(D) Each phase voltage is 60° out of phase with the corresponding load voltage
Answer: Option A
13. Which one of the following is not the function of pole shoes in a D.C. machine?
(A) To reduce eddy current loss
(B) To support the field coils
(C) To spread out flux for better uniformity
(D) To reduce the reluctance of the magnetic path
Answer: Option A
14. Laminated cores, in electrical machines, are used to reduce
(A) Copper loss
(B) Eddy current loss
(C) Hysteresis loss
(D) All of the above
Answer: Option B
15. The magnetic reluctance of a material
(A) Decreases with increasing cross sectional area of material
(B) Increases with increasing cross-sectional area of material
(C) Does not vary with increasing cross-sectional area of material
(D) Any of the above
Answer: Option A