Basic Electrical Engineering

Electrical Circuit Analysis Viva Questions

Electrical Circuit Analysis Viva Questions

Electrical Circuit Analysis Viva Questions, Viva Questions on Electrical Circuit Analysis, Short answer type questions on Electrical Circuit Analysis, Engineering Viva Questions, Basic Electrica Engineering Viva Questions.

Short Answer Type Questions with Answers

Q.1. What is electric current?

Ans. The controlled movement of electrons (or drift) through a substance, is called the elect current.

Q.2. What is the difference between emf and potential difference?

Ans. EMF (electromotive force) is the force that causes a current to flow in an electric circuit while the potential difference between any two points in an electric circuit is that different in their electrical state which tends to cause the flow of electricity from one point to the other.

Q.3. What is meant by electrical resistance?

Ans. Resistance may be defined as the property of a substance that opposes (or restricts) the flow of electric current (or electrons) through it.

Q.4. What is Ohm’s law?

Ans. Physical state i.e. temperature rise etc. remaining the same the current flowing through a conductor is directly proportional to the potential difference applied across its ends.

Q.5. What are the limitations of Ohm’s law?

Ans. Ohm’s law cannot be applied to the circuits consisting of (i) electronic tubes or transistors (because such elements are not bilateral) and (ii) non-linear ‘elements such as powdered iron, electric arc, etc.

Q.6. How does the resistance of a homogeneous material having constant length vary with changing cross-sectional area?

Ans. Resistance of a homogeneous material having constant length is inversely proportional to its area of x-section i.e. R α 1/a

Q.7. What is meant by specific resistance of material?

Ans. The specific resistance, also called resistivity, is equal to the resistance of the material of unit length having unit cross-sectional area.

Q.8. Give the relations between (i) kWh and kcal and (ii) kWh and megajoules.

Ans. (i) 1 kWh = 860 Kcal (ii) 1 kWh = 3.6 MJ

Q.9. What is an electric network?

Ans. An electric network is an interconnection of physical electrical devices such as an energy source (or sources), an energy convertor or convertors (load or loads), and conductors that connect them.

Q.10. What is an energy source?

Ans. An energy source (or source), such as a primary or secondary cell, a generator, and the like, is a device that converts chemical, mechanical, thermal, or some other form of energy into electrical energy.

Q.11. What is an energy converter?

Ans. An energy converter also called the load, such as a lamp, heating appliance, or electric motor, converts electrical energy into light, heat, mechanical work, etc.

Q.12. What is meant by ‘node’?  

Ans. A junction or node is a point in a network where two or more branches meet.

Q.13. Distinguish between mesh and loop of the network.

Ans. A loop is a closed path in a network formed by a number of connected branches. Mesh is a loop that contains no other loop within it.

Q.14. What is the utility of the superposition theorem?

Ans. This theorem is applied when we are to determine the current in one particular branch of a network containing several voltage sources or current sources or both voltage sources and current sources.

Q.15. What is the utility of the Thevenin theorem?

Ans. Thevenin’s theorem is advantageous when we are to determine the current in a particular element of a linear bilateral network particularly when it is desired to find the current which flows through a resistor for its different values. It makes the solution of the complicated networks (particularly electronic networks) quite simple.

Q.16. What is the maximum power transfer theorem?

Ans. A resistive load, served through a resistive network, will abstract maximum power when the load resistance value is the same as the resistance “viewed by the load as it looks back into the network”.

Q.17. Give the relationship between resistances connected in delta and equivalent star system.

Ans. The equivalent star resistance connected to a given terminal is equal to the product of the two delta resistances connected to the same terminal divided by the sum of the delta-connected resistances.

Q.18. Give the relationship between resistances connected in star and equivalent delta systems?

Ans. The equivalent delta resistance between two terminals is the sum of the two-star resistance connected to those terminals plus the product of the same divided by the third-star resistance.  

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