Question 1

**PART-A**

Accepted Answer

Phasor representation uses a right-angled Power Triangle to visualize the relationship between Active, Reactive, and Apparent power.

Question 2

State Kirchoff's voltage law.

Accepted Answer

Kirchhoff's Voltage Law (KVL) dictates that the total algebraic sum of voltages around any closed loop in an electrical circuit must equal zero.

Question 3

What is fuse?

Accepted Answer

A fuse is a critical sacrificial safety device containing a low-melting-point wire that melts to break the circuit during overcurrent conditions.

Question 4

State the torque-slip characteristics of induction motor.

Accepted Answer

The torque-slip characteristic curve of an induction motor depicts how output torque changes non-linearly as slip increases from 0 (synchronous speed) to 1 (standstill).

Question 5

Discuss the transformer EMF equation.

Accepted Answer

The transformer EMF equation relates the induced voltage to the supply frequency, the maximum core flux, and the number of winding turns.

Question 6

What are the transformer losses?

Accepted Answer

Transformer losses are divided into constant Core (Iron) losses and variable Copper losses.

Question 7

What is BJT?

Accepted Answer

A Bipolar Junction Transistor (BJT) is a three-terminal, current-controlled semiconductor device used extensively for electronic switching and signal amplification.

Question 8

Explain working principle of induction motor.

Accepted Answer

An induction motor operates on the principle of electromagnetic induction driven by a Rotating Magnetic Field.

Question 9

Explain MCB.

Accepted Answer

An MCB (Miniature Circuit Breaker) is an automatic electromagnetic switch designed to instantly protect circuits from overcurrents and short circuits.

Question 10

What is resonance?

Accepted Answer

Resonance in an AC circuit occurs when the inductive and capacitive reactances exactly cancel each other out, making the circuit purely resistive.

Question 11

**PART-B**

Accepted Answer

The Maximum Power Transfer Theorem defines the exact condition required to transfer the absolute maximum amount of power from an active source network to a load resistor.

Question 12

For the circuit shown in Fig. find VCE and VAG.

Accepted Answer

Calculating nodal voltages like VCE and VAG requires systematic application of Kirchhoff's laws to the provided circuit schematic.

Question 13

An alternating voltage is given by V=230sin 314t. Calculate frequency and max…

Accepted Answer

By analyzing the standard sinusoidal equation V = 230 sin(314t), we determine the frequency is 50 Hz, Maximum is 230V, RMS is 162.63V, and Average is 146.42V.

Question 14

Describe the construction details of single phase transformer.

Accepted Answer

A single-phase transformer is constructed primarily of a laminated silicon steel magnetic core and two highly insulated copper windings (Primary and Secondary).

Question 15

With a neat circuit diagram, explain the construction and principle of operat…

Accepted Answer

A DC machine consists of a stationary magnetic field system and a rotating armature with a commutator, working on Lorentz force or Faraday's induction principles.

Question 16

Explain IGBT in detail with neat diagrams.

Accepted Answer

An Insulated Gate Bipolar Transistor (IGBT) is an advanced power semiconductor that combines the high-speed, voltage-controlled gate of a MOSFET with the high-current, low-saturation-voltage capability of a BJT.

Question 17

With suitable example, explain the calculations for energy consumption.

Accepted Answer

Electrical energy consumption is calculated in kilowatt-hours (kWh), also known as 'Units', by multiplying the power rating in kilowatts by the operating time in hours.

Question 18

**PART-C**

Accepted Answer

Superposition theorem dictates isolating each source to find partial currents in the 40-ohm resistor, then algebraically summing them.

Question 19

Explain about Star and Delta connected three phase balanced circuits.

Accepted Answer

Three-phase balanced circuits are connected in either a Star (Y) configuration, featuring a neutral point and varying voltages, or a Delta (Δ) configuration, featuring a closed loop and varying currents.

Question 20

Explain the tests on a single phase transformer and develop an equivalent fro…

Accepted Answer

The Open Circuit (OC) and Short Circuit (SC) tests are vital diagnostic procedures used to determine transformer core losses, copper losses, and equivalent circuit parameters without fully loading the device.

Question 21

Explain the different characteristics of DC Motor.

Accepted Answer

DC motor characteristics are graphical representations showing how Torque varies with Armature Current, Speed with Armature Current, and Speed with Torque, dictating motor suitability for industrial tasks.

Question 22

Explain different types of Earthing with suitable diagram.

Accepted Answer

Earthing is a critical safety practice linking non-current-carrying metal parts of appliances to the ground mass. Pipe and Plate earthing are the most common industrial methods.

Basic Electrical Engineering