Hole is

Options

A. (a) an anti - particle of electron
B. (b) a vacancy created when an electron leaves a covalent bond
C. (c ) absence of free electons
D. (d) an artificially created particle

Explanation

### Step-by-Step Solution

1. **Definition of Hole**:
A hole is defined as a vacancy created when an electron leaves a covalent bond in a semiconductor material. It is not an antiparticle of an electron, nor is it a free electron or an artificially created particle.

2. **Understanding Semiconductors**:
Semiconductors can be doped with impurities to create two types: n-type and p-type. In p-type semiconductors, holes are the majority charge carriers.

3. **Doping Process**:
When a semiconductor like silicon is doped with a trivalent atom (e.g., aluminum), it has three valence electrons. This means that it can form only three covalent bonds with neighboring silicon atoms, leaving one silicon atom with a missing electron, thus creating a hole.

4. **Behavior of Holes in Electric Field**:
When an electric field is applied across a p-type semiconductor, electrons from the neighboring covalent bonds can move to fill these holes. As an electron moves to fill a hole, it creates a new hole where it was originally located. This movement of holes can be visualized as holes moving in the opposite direction to the flow of electrons.

5. **Conduction of Electricity**:
The movement of holes, along with the movement of electrons, facilitates the conduction of electricity in the semiconductor. Holes can be thought of as positive charge carriers since they represent the absence of negatively charged electrons.

### Summary
In summary, a hole is a vacancy left by an electron in a covalent bond within a semiconductor. It plays a crucial role in the conduction of electricity, especially in p-type semiconductors where holes are the majority carriers.