BEE VIVA QUESTIONS PDF

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Experiment: 01 Aim: To Verify Kirchhoff's Law Viva Voce

Q.1 Ans. Q.2 Ans. Q.3 Ans. Q.4 Ans. Q.5 Ans. Q.6 Ans.

Q.7 Ans. Q. 8 Ans.

Q.9 Ans. Q.10 Ans.

What is electric current? Flow of electrons is called electric current. Define Electric Potential? The capacity of charged body to work is called electric potential. What is Resistance? The property of material by virtueof which it opposes or resist the flow of current is known as resistance. Define Electric Energy? The total amount of work done in an electric circuit is known as electric energy. What is Electric Power? The rate at which work is done in an electric circuit is known as electric power. On what factors do the resistance offered by couductor depends on? 1. It is directly proportional to its length. 2. It is inversely proportional to the area of cross-section of conductor. 3. Depends on temperatureof the conductor. 4. Depends on nature of material of conductor. What is conductance? The property of conductor due to which it allows the current to pass through it is known as conductance. State Ohm's Law It states that “for any conductor potential difference (V) between two ends and current (I ) flowing between two ends of conductor are directly proportional to each other”. State Kirchhoff's voltage Law. “The algebric sum of product of current and corresponding resistance in closed circuit is equal to the electromotive force in that circuit”. State Kirchoff's current Law. “The algebric sum of the currents meeting at a node of electrical circuit is zero or at any node sum of incoming current is always equal to sum of outgoing currents”.

Experiment : 02 Aim : To study Superposition Theorem Viva Voce Q.1 Ans.

What is bilateral network? A circuit or network in which the magnitude of current remains constant when the polarity of source is reversed is called bilateral network. Q.2 What are Passive Elements? Ans. A passive element is an electrical component that does not generate power, but instead dissipates, stores, and/or releases it. Passive elements include resistances, capacitors, and coils (also called inductors). Q. 3 What are Active Elements? Ans. The active elements generate energy. Batteries, generators, operational amplifiers, etc are active elements. Q. 4 State Superposition theorem Ans. “In a linear and bilateral network containing two or more than two source of emf , the current flowing through any branch is algebric sum of currents that would be produced due to each emf while acting alone and other sources of emf are to be replaed by their internal resistances ”. Q.5 Why voltage souce is short circuited in superposition theorem? Ans. The internal resistance of ideal voltage source is zero. Hence while deactivating voltage source in superposition theorem, it is short circuited indicating zero internal resistance. Q.6 Why Current souce is open circuited in superposition theorem? Ans. The internal resistance of ideal current source is infinite. Hence while deactivating current source in superposition theorem, it is open circuited indicating infinite internal resistance.

Experiment no : 03 Aim: To plot the B-H curve of transformer to study the behaviour of Magnetic Material Viva Voce Q.1 What is Flux Density? Ans. The number of flux passing per unit area is called flux density. Q.2 Define Magnetomotive force Ans. It is the force which drives the flux through the magnetic circuit. In case of electromagnet , it is given by product of currentand number of turns in the coil. Q.3 Define magnetic field intensity Ans. It is defined as magnetomotive force per unit length of magnetic path. Q. 4 Explain the term : Paramagnetic materials Ans. The materials, which are not strongly attracted by the magnet, such as aluminium, tin, platinum, magnesium, manganese etc. are known as paramagnetic materials. The relative permeability is small but positive. Q.5 Explain the term : Diamagnetic materials Ans. The materials which are repelled by a magnet such as zinc, mercury,lead,sulphur, copper,silver etc. are known as diamagnetic materials. The permeability is slightly less than unity. Q. 6 Explain the term : Ferromagnetic materials Ans. The materials, which are strongly attracted by the magnet, such as iron, steel, nickel, cobalt etc. are known as ferromagnetic materials. The permeability is very high. Q. 7 What is permeability ? Ans. The ability of material to conduct flux is known as permeability. More the permeability, more is the flux and hence stronger is the magnet. Q. 8 Define Reluctance. Ans. The opposition offered to the flow of flux by magnetic path is called reluctance. Q. 9 What is permeance? Ans. The reciprocal of reluctance is known as permeance of magnetic circuit. Q.10 What do you mean by leakage flux? Ans. It is that flux which does not follow its intended or desired path in a magnetic circuit. Q.11 What do you mean by residual flux? Ans. It is the flux which remains in a sample of magnetic material after the magnetising force reduced to zero. Q.12 What is coercivity? Ans. It is the amount of magnetising force required to reduce the retained magnetism to zero.

Experiment no : 04 Aim : To determine R and L of choke coil Viva Voce

Q. 1 What is mean by inductive reactance? Ans. Opposition to the flow of alternating current offered by inductance is known as inductive reactance. Q.2 What is mean by capacitive reactance? Ans. Opposition to the flow of alternating current offered by capacitance is known as capacitive reactance. Q.3 Define impedance Ans. A combination of resistance, inductive reactance and capacitive reactance in an AC circuit is termed as impedance.

Experiment no: 05 Aim: To study R-L-C series circuit Viva Voce Q. 1 Define Time Period Ans. Time required to complete one cycle is called time period. Q. 2 Define Frequency Ans. Number of cycles per second is called as frequency of alternating quantity. Q. 3 Define root mean square (RMS) value. Ans. It is the value od DC current which, when flowing through a given circuit for a given period of time, produces the same heat as produced by alternating current when flowing through the same time. Q. 4 Define average value. Ans. The average value of an alternating current is that DC current which transfers across any circuit the same charge as it is transferrred by that alternating current during the same time.

Experiment no: 06 Aim : To study R-L-C Parallel Circuit Viva Voce Q.1 What is form factor? Ans. The ratio of RMS value to Average value is the form factor. Q. 2 Define Crest Factor Ans. It is the ratio of maximum value to RMS value. Q. 3 What is mean by inductive reactance? Ans. Opposition to the flow of alternating current offered by inductance is known as inductive reactance. Q.4 What is mean by capacitive reactance? Ans. Opposition to the flow of alternating current offered by capacitance is known as capacitive reactance. Q.5 Define impedance Ans. A combination of resistance, inductive reactance and capacitive reactance in an AC circuit is termed as impedance. Q.6 Define Power Factor Ans. Power factor is defined as the ratio of active power to apparent power. Q. 7 What is Q- factor? Ans. The efficiency of inductance and capacitance to store energy is measured in terms of a factor called as Quality facor or Q- factor.

Exrperiment no : 07 Aim : To perform Open circuit test and short circuit test on single phase transformer Viva Voce Q. 1 What do you mean by electromagnetic induction? Ans. According to faradays's law, whenever the flux linked with the conductor of coil changes an emf is induced in that coil and the amount of this induced emf is directly proportional to the rate of change of flux linked with the coil. Q.2 Explain the concept of ideal transformer Ans. An ideal transformer is one which has no losses i.e it's windingg have no ohmic resistance, there is no magnetic leakage and hence which has no heating and core lossses. In other words an ideal transformer consists of two purely inductive coils wound on a loss free core. Q. 3 How many losses are there in transformer? Ans. There are two types of losses i.e iron losses and copper losses.Q.48 What is the main purpose of using core in transformer? Ans. To decrease the reluctance of magnetic circuit Q.4 Why transformer cores are laminated? Ans. In order to reduce eddy current losses Q.5 What is the purpose of isolation transformer? Ans. It is used to isolate primary winding from secondary winding.

Experiment No: 08 Aim : To determine efficiency and voltage regulation of a single phase transformer by direct loading method Viva Voce Q.1 Ans.

Define Symmetrical or balanced supply system. The three phase system in which three phase voltages are of identical magnitudes and frequency and are displaced by 120 degree from each other is called as symmetrical system. Q.2 Define Efficiency of transformer. Ans. Efficiency is defined as ratio of output power to input power. Q.3 What will happen if DC supply is given to transformer ? Ans. The heating losses in case of DC supply is very large so that is will burn the primary winding causing permanent damage to the transformer. Q.4 Why transformer is rated in VA or KVA? Ans. The copper losses in transformer are dependent on current and iron losses are dependent on voltage. Hence total losses depends on volt ampere(VA) and not on the power factor. Therefore rating of transformer is in VA or KVA and not in W or KW. Q.5 Explain the concept of ideal transformer Ans. An ideal transformer is one which has no losses i.e it's windingg have no ohmic resistance, there is no magnetic leakage and hence which has no heating and core lossses. In other words an ideal transformer consists of two purely inductive coils wound on a loss free core....