Engineering Viva Questions

  Semiconductor Devices Viva Questions Q.1. What is doping? Ans. The process of adding impurity to a pure semiconductor is called doping. Doping is done at a rate such that only one atom of impurity is added per 10 6 to 10 10 semiconductor atoms. Q.2. What are the types of extrinsic semiconductor? Ans. Depending upon the types of impurity added, there are two types of extrinsic semiconductors: (a) N-type semiconductor (b) P-type semiconductor Q.3. What is the energy gap? Ans. The energy gap between the valence band and conduction band is known as the forbidden energy gap. A forbidden energy gap is a region in which no electron can stay as there is no allowed energy state. The greater the forbidden energy gap more tightly the valence electrons are bound to the nucleus. Q.4. Define diode resistance. Ans. An ideal diode offers zero resistance when forward bias and infinite resistance when it is reverse biased. But practical or real diode does not beha...

Viva Question on Single Phase AC Circuits Q.1. What is the phase relationship between the supply voltage and current flowing through a purely resistive circuit? Ans. Both supply voltage and circuit current are in phase with each other. Q.2. What is the phase relationship between the supply voltage and current flowing through a purely inductive circuit? Ans. In a purely inductive circuit current lags behind the supply voltage by 90° or π/2 radians. Q.3. Why are the inductors usually iron cored? Ans. Inductors or choke coils are made of the iron core because large valued flux densities cab be produced in iron cores and so inductances of large value can be had. Air-cored inductors become too much bulky to provide an inductance of a required value. Q.4. Does an inductance draw instantaneous power as well as average power? Ans. An inductance draws instantaneous power but no average power. The power drawn by inductance during a one-quarter cycle is released in anothe...

Viva Questions of Materials in Basic Mechanical Engineering Viva Questions and Answers MATERIALS Q. 1. Classify the engineering materials of construction. Ans. Engineering materials of construction can be classified as (1) Metallic materials : (a) Ferrous material (b) Non- ferrous material (2) Non-metallic materials: (a) Organic material (b) Non-organic material. Q. 2. What are the mechanical properties of material? Ans. The mechanical properties of materials define the behavior of materials under the action of external forces, called loads. They are a measure of the strength and lasting characteristics of a material. Q. 3. Define the term 'strength' of a material. Ans. The strength of a material is its capacity to withstand the action of external loads. The stronger the material the greater the load it can withstand. Q. 4. What is elasticity? Ans. Elasticity is that property of a material by virtue of which deformation caused by applied load disappears upon removal...