electrical engineering important question unit wise

                                                                                       B. Tech. First Year

                                   QUESTION BANK

 

  Session: 2022-2023                                                                                  Semester: 1st

UNIT 1

Q1. Explain Active and Passive element 

Q2. Explain ideal and practical voltage and current source.

Q3. Give two comparison between unilateral and bilateral elements Q4. Define linear and nonlinear elements with examples. Q5. State and explain Kirchhoff’s voltage law.

Q6. What are the limitations and applications of Kirchoff’s Law in circuit theory explain? Apply KVL and KCL to solve the problem of Q7 and Q8. Q7. Find current in 2-ohm resistance in the following figure using mesh analysis method 

 

Q8. Using mesh analysis, find the current through 6-ohm resistances in the following circuit.

 

Q9.  Using the Nodal method, find the current through resistor r2 in the given figure below

 

Q10 . Use nodal analysis to find the voltage across and current through 4 Ω resistor in Figure given below:  

  

 

UNIT-2

1.            Calculate the average value, RMS value, form factor and peak factor of full and half sinusoidal waveform.

2.            What do you mean by phasor representation?

3.            Derive the current and power in R-L-C series circuit. What do you mean by Apparent, active and reactive power?

4.            Explain the Resonance in series R-L-C circuit and quality factor and also define why q- factor in series circuit known as voltage magnification factor.

5.            Explain parallel resonance and what do you mean by dynamic impedance.

6.            Determine Bandwidth and also determine upper and lower half power frequency.  

7.            Explain the causes and effects of low PF and how to improve the low Power factor connected system.

8.            A star connected load consists of 6 Ω resistance in series with 8Ω inductive reactance in each phase. A supply of 440 v at 50 Hz is applied to the load. Find the line current, power factor and power.

9.            Derive the relation between Line and phase voltage/Current relations in case of 3ɸ Delta connected system.

10.         Each phase of delta connected load consists of a 50Ω resistor in series with a 50μF capacitor. The supply is 440V, 3-phase, 50Hz. Determine phase current, line current and power consumed.

11.         Derive the relation between Line and phase voltage/Current relations in case of 3ɸ star.

Unit-3

Q1. A) Compare electric & magnetic circuits. 

B)  define i) Reluctance ii) permeability iii) MMF. 

C)  explain the properties of magnetic materials.

Q2. Draw and explain the Magnetic Hysteresis.

Q3. What do you mean by magnetic materials? Explain.

Q4. Explain the working principle of Single-phase Transformer. Why transformer not used on DC supply.

Q5. Derive the EMF Equation of 1ɸ transformer.

Q6. Derive the condition for maximum efficiency. Also derive load at maximum efficiency.

Q7. Draw and explain the Equivalent circuit of 2- winding transformer. Also explain the working of transformer on no load and on load conditions with phasor diagram.

Q8. Define Auto transformer with their advantages and disadvantages. Also explain the connection of 3 ɸ transformer.

Q9.A 250 kVA single phase transformer has iron loss 1.8 kW. The full load copper loss is 2000W. Calculate, - i) efficiency at full load, 0.8 lagging

p.f. ii) kVA supplied at maximum efficiency iii) maximum efficiency at 0.8 lagging p.f. or

The efficiency of a 400 kVA, single-phase transformer is 98.77 % at full load 0.8 p.f. and 99.13 % at half load unity p.f. Find i) Iron losses at full and half loads.

Q 10. Draw the no load phasor diagram of a transformer.

 

UNIT-4

Q1. Derive the EMF equation of DC Machine. Also derive the torque equation of DC motor.

Q2. A 20 kW, 250V dc shunt generator has armature and field resistances of

0.1Ω and 125Ω respectively. Calculate the total armature power developed when running (i) as a generator delivering 20 kW output (ii) as a motor taking 20 kW input.

Q3. A 4-pole, 3-phase induction motor operates from a supply whose frequency is 50 Hz.

Calculate i) the speed at which magnetic field of the stator is rotating the speed of rotor when slip is 0.04  ii)the frequency of the rotor current when the slip is 0.03 iii)the frequency of the rotor current at standstill

Q4. Explain the Construction and working principle of 3-phase Induction motor. 

Q5 Why 1-phase IM is not self-starting. Illustrate the methods of starting.

 Q6 Why 3ɸ Synchronous motor is not self-starting.

Q7.Explain the construction & working principle of 3ɸ Synchronous motor.

Q8. Draw the Torque-slip characteristic of 3-phase IM.

Q9. Draw the Characteristics of DC Motor.

 

UNIT-5

Q1 Explain (i) MCB (ii) MCCB (iii) ELCB (iv) SFU

Q2 Explain the construction, ratings and specific applications of types of wires and cables used in electrical engineering.

Q3. Explain the requirement of earthing for electrical equipment. What is the difference between neutral and earthing? Explain pipe and plate earthing.

Q4. What is the difference between primary and secondary batteries? What are the factors that affect the battery capacity? Also explain the electrical characteristics of lead-acid and Li-Ion battery.

Q5. A battery has taken a charging current of 5.2 A for 24 hours at a voltage of 2.25 V, while discharging given a current of 4.5 A for 24 hours at an average voltage of 1.85V. calculate the quantity efficiency & the energy efficiency of the battery.