# SSC JE Electrical Important MCQ Part 7

SSC JE Electrical Important MCQ PDF Part 7

1.At resonance frequency, the inductive reactance value is the same as

A) Reactance of the capacitor

B) Impedance of the circuit

C) Resistance of the circuit

D) Reactance of the coil

Answer  : A (At the resonant frequency fr, XL = XC)

2.Which of the following is NOT a standard transmission voltage

A) 222 kV

B) 750 kV

C) 400 kV

D) 132 kV

Answer  : A (Nominal System Voltage in kV 132 220 275 345 400 500 750 Maximum Operating Voltage in kV 145 245 300 362 420 525 765)

3.If there are “n” nodes in the circuit there will be ________ independent nodal equations.

A) n+1

B) n-2

C) n

D) n-1

4.Open circuit test on transformers is conducted to determine which of the following

A) Core losses

B) Eddy current losses

C) Hysteresis losses

D) Copper losses

Answer  : A (Open circuit test is conducted to find the core/iron loss of a transformer,Core losses is the sum of the hysteresis loss and the eddy current loss)

5.Which of the following motors is employed in hair dryers

A) Capacitor start induction motor

B) Split phase induction motor

C) Capacitor start capacitor run induction motor

6.The wire of 2 SWG is equivalent to diameter of

A) 7.01 mm

B) 5.89 mm

C) 5.38 mm

D) 6.4 mm

Answer  : A (1 Swg = 7.620mm,2 Swg = 7.010mm,3 Swg = 6.401mm,4 Swg = 5.893mm,5 Swg = 5.385mm)

7.Which of the following diodes is a signal diode

A) 0A79

B) BY127

C) 1N4007

D) DR25

Answer  : A (0A79 diodes-The symbol ‘A’ indicates that this device is made from germanium,As germanium has less cut in voltage so this diode is used for low power signal or for signal processing)

8.If a 100 Watts bulb is ON for 10 hours, then what will be the amount of electricity consumed

A) 1500 Watts

B) 1 kWh

C) 300 Watts

D) 100 Watts per hour

Answer  : B (Amount of electricity consumed=100 x 10 = 1000 Watt-Hour = 1 Kilowatt-Hour (kWH) = 1 units)

9.If the battery of a multimeter becomes weak, then it will give

10.A component which is used to close or break a circuit is called

A) Electric cell

B) Wire

C) Switch

D) Bulb

11.Which of the following is a possible cause of blackening at both ends of the fluorescent lamp

A) Frequent starting of fluorescent lamp

B) Improper ballast

C) Low or high voltage

D) All of these

12.When the rotor of a three-phase induction motor runs at synchronous speed, its rotor frequency will become

A) Zero

B) Half of supply frequency

C) Equal to the supply frequency

D) Double the supply frequency

13.The total opposition offered to the flow of current in AC circuit is called

A) Inductance

B) Resistance

C) Impedance

D) Capacitance

14.To measure which of the following is Wheatstone bridge method used

A) Voltage

B) Resistance

C) Power

D) Current

15.In a megger, controlling torque is provided by

A) Gravity

B) Eddy current

C) Coil

D) Spring

16.The spindle of the moving system in a PMMC instrument is supported at both ends with the help of

A) Bush bearings

B) Jewelled bearings

C) Gun metal bearings

D) Steel bearings

17.The electric displacement of a winding in two-phase supply is

A) 180°

B) 90°

C) 120°

D) 60°

18.In a 2 pole lap winding DC machine, the resistance of one conductor is 2 Ω and the total number of conductors is 100. Find the total armature resistance.

A) 200 Ω

B) 50 Ω

C) 100 Ω

D) 10 Ω

Answer  : B (Total armature resistance=X×Z/A² Where X = Resistance of one conductor Z = Total number of conductors A = No of parallel paths-For lap winding it is 2,So total armature resistance=2×100/2²=50 Ω)

19.The rotor in an alternator requires

A) Pulsed DC

B) Triangular wave

C) AC

D) DC

Answer  : D (An alternator is a synchronous machine and the field winding on the rotor is designed for DC)

20.Three-phase transformer contains

A) One primary and three secondary windings

B) Three primary and one secondary windings

C) Three primary and three secondary windings

D) Three primary and two secondary windings