Important Question for Final Exam

1.	Derive the expression for the equivalent resistance of a number of resistances connected in series and a number of resistances connected in parallel. Or Give the comparison of series and parallel circuit
2.	Define temperature co-efficient of resistance. How resistances of different materials vary with temperature? Prove that αt = α0/(1+ α0 t) Or Prove that α t = α0 / (1+ α0t) and α 2 = 1/ [(1/ α1) + (t2-t1)].
3.	Explain the method of transforming a star network of resistances into delta network.  Explain the method of transforming a delta network of resistances into star network
4.	Explain KCL and KVL
5.	Giving reason in brief, state the effect of increase in temperature on the resistance of (i) pure metals (ii) insulators (iii) semiconductors
6.	With reference to electrostatic and capacitance State Coulomb’s laws and explain it.Define: (a) electric field intensity (b) electric potential (c) potential gradient (d) permittivity (e) Capacitance
7.	Obtain the expression for the capacitance of a parallel plate capacitor with uniform dielectric medium and the capacitance of a parallel plate capacitor with plate area ‘A’ and distance of separation between the plates ‘d’ in M.K.S and the expression for the capacitance of a parallel plate capacitor with partly air medium.
8.	Derive the expression for energy stored in the capacitor Or Derive The Expression Of Energy Stored in a capacitor of ‘C’ farad when voltage ‘V’ is applied across it
9.	Explain the following terms: (i) Magneto motive force (ii) Magnetic field Intensity (iii) Reluctance (iv) permeability (vi) fringing effect ( vii) leakage coefficient
10.	Give the comparison between electrical and magnetic circuits. Or Give the dissimilarities of electrical and magnetic circuits.
11.	Explain magnetic hysteresis in detail.Or Draw B'H curve (Magnetising curve) of a magnetic material and label the figure. Define all the terms relevant to this curve.
12.	State and explain Faraday’s laws of electromagnetic induction also Explain Lenz’s law and faraday’s law of electromagnetic induction.
13.	Discuss statically induced e.m.f and mutually induced e.m.f. Or Discuss statically induced e.m.f and mutually induced e.m.f
14.	State and explain self inductance (L). Derive expression of coefficient of mutual coupling between two coils having self inductances of L1 and L2.
15.	Derive the expressions of equivalent inductance, when two magnetically coupled coils are connected in series in two different ways. Or Two inductive coils are connected in parallel. Derive the expression for total inductance when (i) coils are in parallel aiding connection (ii) coils are in parallel opposing connection
16.	Explain generation of 3-Ф alternating emf OR AC voltage.
17.	Derive the relationship between line voltage & phase voltage in a 3-phase star-connected circuit.
18.	Derive the relationship between line voltage & phase voltage in a 3-phase delta-connected circuit.
19.	Prove that power in a 3-phase balanced circuit can be deduced from the readings of two watt meters. Draw the relevant connection and phasor diagrams. Discuss the nature of power factor (i) when two readings are equal and positive (ii) when two readings are equal but opposite in sign (iii) when one wattmeter reads zero. Or Prove that the sum of readings of two watt meters connected to measure power in 3- phase a.c. circuit, gives total power consumed by the circuit.
20.	Explain effect of power factor on the readings of the two wattmeter connected to measure the power.
21.	Discuss resonance in R-L-C series circuit. Explain how pf, XL and R vary with frequency.
22.	Explain generation of alternating EMF or AC voltage. Or Derive EMF equation of alternating EMF or AC voltage. Or Derive EMF equation of AC current.
23.	Define average value and RMS value. Explain average value and RMS value in case of sinusoidal current & half wave rectifier.
24.	Prove that in a purely capacitive circuit power consumed is zero when a.c. voltage is applied. Draw relevant phasor diagram and waveforms.Or  Prove that in a purely inductive circuit power consumed is zero when a.c. voltage is applied. Draw relevant phasor diagram and waveforms. Or Prove that in a purely resistive circuit power consumed is zero when a.c. voltage is applied. Draw relevant phasor diagram and waveforms.
25.	Draw the phasor diagram in R-L circuit. Draw impedance triangle and power triangle Or Draw the phasor diagram in R-C circuit. Draw impedance triangle and power triangle Or Explain series R-L-C circuit with the phasor diagram for XL>XC; XL<XC &XL=XC
26.	Explain construction and working of lead acid battery
27.	Explain the phenomena of electrical resonance in R –L –C series circuit connected to variable frequency supply. Draw relevant vector diagram& define Q factor of the circuit.
28.	Differentiate primary and secondary cell.
29.	Define the following term: (1) RMS value (2) Average value (3) Form factor (4) Peak factor regarding a.c.quantity.
30.	Explain the following methods of charging a battery (i) Constant current method (ii)Constant voltage method
31.	Draw and explain wiring diagram of supply mains with energy meter and distribution box.
32.	Explain the construction of cable with functions of its various parts with the help of neat diagram. Also give the classification of cable.
33.	Draw a schematic block diagram showing positioning of major equipments in domestic wiring. Label the diagram. Also draw the circuit for controlling one lamp from two points (stair case wiring).
34.	Write a short note on: Cleat wiring , conduit wring
35.	General guideline for wiring of domestic installation with neat sketch for position of equipment.
36.	Classify and describe various types of lighting schemes.
37.	Explain the wiring diagram of a tube light with choke and glow starter.
38.	Define: (i) luminous flux, (ii) Lux (iii) Illumination (iv) Plane angle (v) Solid angle (vi) Lamp efficiency
39.	Give comparison between fuse and MCB with regard to protection in wiring installation.
40.	Give the circuit diagram of ELCB. Explain its working in brief.
41.	Explain the working of a miniature circuit breaker(MCB).
42.	What is earthing? Explain requirement of earthing for any electrical equipment.
43.	List various protective devices used in the electric circuits and compare working of ELCB with MCB.
44.	What is the function of fuse in an electrical circuit? State the desirable properties of fuse element.