# be1

## 1) What is an Electric Potential?

The potential of a particular point, is defined as the work done to move a positive charge particle to move to that point in opposite to electric field. It may be an external energy applied to move that positive charge or may be internal potential energy of the positive charge.

## 2) What is Potential Difference?

The differential in potentials at two points in an electric field is called as potential difference between two points. It is measure in Volts i.e. VAB is called the potential difference between points A & B. If the VAB is positive then it illustrates that the potential at point A is high compared to potential at point B. In this case there will be chance of movement of charged particle from A to B against to electrical field between the points.

VAB = VA – VB

## 3) What is a Transit time of an Electron?

The time taken by an electron to travel from one electrode to the other electrode is called electron transit time. It is denoted as ‘τ’.

${\color{DarkBlue}&space;\tau&space;=\sqrt{\frac{2*m}{e*V}}*d}$

Where  V = Potential applied to electron

d= Distance between electrodes

e = Electron charge

m = mass of an electron

Note: The  transit time of an electron decreases with the increase in potential (V).

## 4) What is an Electron Volt(eV)?

One Electron volt is the energy gained by the electron when it falls from one point to another point which has a potential difference of 1 volt. I.e. under potential difference of one volt, the electron moves from higher potential to lower potential, during this free fall in the electron field it gains an electron volt energy.

In other case it the energy required to move an electron in the potential difference of one volt. This is against to the electric field.

1 electron volt  = 1.60217657 × 10-19 joules

#### 5) What is an Electric Field intensity(ε)?

The force experienced by an electric charge particle at a point by an electric field is called as Electric field intensity. It is denoted as ε and its unit is V/m (Volts/meter).
${\color{Blue}&space;\varepsilon&space;=\frac{f}{q}}$

${\color{Blue}&space;\varepsilon&space;=&space;\frac{V}{d}}$

## 6) What is an Ionization Potential?

The energy required to detach an loosely coupled electron from the influence of parent nucleus is called ionization potential.

## 7) What is an electron spin?

The electron generally orbits around the parent nucleus and in addition to this it also rotates around itself like an earth. This intrinsic angular momentum property of en electron is called electron spin. There are only two direction of spins when it is subjected to a magnetic field i.e. either parallel or anti-parallel to the field.

## 8) What is N type Semiconductor?

When extra valance electrons are introduced in a pure semi-conductor material (silicon) by putting or injecting dopants or impurities, an N-type material is produced. The dopants are used to create an N-Type material are Group-V elements in the materials table.

N-type semiconductor bond diagram

Group V elements: Arsenic, antimony, phosphorus.

In N-type semiconductor electrons are majority carriers and holes are minority carriers.

## 9) What is P- Type Semiconductor?

When a dopant from Group III elements from the elements table is introduced in to pure semiconductor, produces a P-Type semiconductor. The Group III elements have only 3 valance electrons in its outer orbit which there combines with four valance electrons semiconductor material (silicon). This results in missing of electron which creates a hole (P+) , or positive charge that can freely move around in the material.

P-type semiconductor bond diagram

Group III elements: aluminum, boron, and gallium.

In P-Type semiconductor, holes are the majority carriers and electrons are the minority carriers.

## 10) What are passive and active components?

Passive components: The components which are passive in nature i.e. which can attenuate the input applied signal to a desired level. These are energy consumers and cannot boost the input signal. Resistors, capacitors and inductors are the examples of passive components.

Active components: The components which plays an active role in the electronic circuit i.e. which can add energy to the input signal are called active components. These can amplify the signal to the desired level. Transistors, operational amplifiers are the examples of active components.

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