## Posts

### energy band gap

what is meant by semiconductor ?Ans.) It is a substance whose properties lie in between conductor and insulators i.e at high temperatures it act as conductor and at low temperature it acts as insulator .the conductivity range of this substance lies in between 10-6 to 104 (W-m) .example :2. what is meant by conductors ?Ans.) conductors are the substance which allows electricity through them ex :-silver,copper etc3.)what is meant by insulators ?Ans.) insulators are the substance which does not allow current to flow through it ex :diamond,graphite .4.) What is the difference in between insulators and conductors ?Ans.) The main difference in between insulators and conductors arises in terms of electrical behavior .the reason for the difference in  electrical behavior of conductors and insulators are due to the difference between their electronic structures .  in conductors free electrons are more and in insulators all electrons are tightly packed . 5.) what is band gap and its units?
Ans.)…

### AC MAIN

what are the apparatus required for the experiment setup of frequency of ac main using an electric vibrator ? Ans.)electric vibrator,frictionless pulley, light weight pan, weights box (10,20,30) scale ,thread .1.)what is meant by stationary waves ?Ans.) when two waves of same frequency and amplitude are travelling through a medium with the same speed but in opposite direction superimpose over each other to form a new(resultant) wave this is known as stationary waves .resultant wave  does not seems to be moving .no net flow of energy is seen A=2acosnx    n=2pie/lamda  what is meant by superposition ? Ans.) when one or more waves moving in same direction and medium pass through each other combine to form a single wave without any disturbance in its energy. this single wave can be expressed as sum of one or more waves . Y=y1+y2+... and so on .what is meant by no…

### viva questions on newtons rings 1.) What are Newton rings ?
Ans.) Dark and bright rings ar formed due to the presence of air film when Plano convex lens is placed on glass plate .

2.) How are Newton's rings formed ?
Ans.) They are formed due to the result of interface between light wave reflected from upper and lower surface of the air film developed between the convex surface of Plano convex lens and Plano glass plate .
3.) What is the function of 45 inclined glass plane in experiment setup ?
Ans.) It turns the light Ray coming from an external source to 90° and so the Ray fall normal on the Plano convex lens .
4.) Why rings get closer as their order increase ?
Ans.) The diameter of the dark frings is directly proportional to the square root of natural numbers .while bright rings are directly proportional to the square root of odd numbers .hence they don't increase at the same rate .
5.) What happens if we us plane glass in experiment setup instead of convex lens ?ans.) The shape of rings will be irregular…

### viva questions on hall effect

Hello friends welcome to my blog .today I am going to say about Viva questions which are commonly asked in experiments during lab evaluation .so let's start our topic .
1.)who introduced the concept of hall effect ?
Ans.) TheHall effect was discovered in 1879 by Edwin Hall while he was working on his doctoral degree at Johns Hopkins Universityin BaltimoreMaryland.

2.)what is hall effect ?
Ans.) Hall effect is defined as "when a current carrying conductor is placed in a magnetic field which is mutually perpendicular to the direction of current,then a potential difference is produced at the right angle sides to both the magnetic and electric field ."

3.) What is hall coeffecient?
Ans.)Ans Hall coefficient is defined as "The ratio of the induced electric field to the product of the current density and the applied magnetic field."
4.) What is hall voltage ?
Ans.)the voltage produced during the process is known as hall voltage .
5.) What is the significance of hall c…