All electrical engineers aspiring to join defence and appearing for exams like SSB, AFCAT or CDS will have to face the personal interview where they are asked varied questions. The interviewing officer however, makes it a point to ask certain technical questions related to the candidate’s subject of study. The main aim is to check the theoretical knowledge of the candidate. Hence, all electrical engineers appearing for the interview must be well versed with the basic concepts.

Important questions which might be asked by the IO

1. What is the electric current?

The flow of electric charge is referred to as electric current. This charge can flow through a wire where it is carried by electrons. Ions carry charge in an electrolyte and both ions and electrons carry charge in plasma.

2. What is ampere?

The unit used to measure the flow of electrons or electric current in a given electric conductor is known as ampere. One ampere of electric current refers to one coulomb of electric charge which is moving through a specific point in one second.

3. Why are AC devices preferred to DC devices?

  • AC devices are preferred to DC since the plant cost required to transmit AC is much less when compared to DC.
  • Another advantage of using AC devices is that these devices use the alternating current which is released through sources of electricity. There is no need to convert it to DC.

4. How does an electric motor work?

A torque or twisting movement is created when a conductor carrying the electric current is placed in a coil (magnetic field). This torque leads to the rotation of the armature or the coil and the electric motor starts working.

5. What is the function of a capacitor in an electrical circuit?

A capacitor is placed in electrical circuits to store electrical energy. It is a passive electrical part with two terminals. It stores electric energy whenever it is charged and subsequently discharges the energy into the circuit whenever it is necessary. Capacitors are used in various electronic devices to maintain electric supply even when the device is not plugged.

6. State the kinds of DC motors.

DC motors can be of three kinds. They are:

  • Shunt motor
  • Service motor, and
  • Compound motor.

7. What is the voltage regulation?

Voltage regulation is the percentage of difference in voltage between two ends i.e. the receiving and sending ends of a distribution or transmission line.

8. What is the difference between a UPS and an inverter?

Both a UPS and an inverter function to store electricity when there is no power. However, the main difference between them lies in their capacity. An inverter has a greater power backup when compared to a UPS.

Although not an exhaustive list, the above questions will surely give a fair idea to all candidates about the kind of questions which might be asked to electrical engineers. The IO’s main aim will be to check the basic knowledge of the candidates. Hence, brushing up all basic theoretical concepts is a must for all candidates.