What are semi-conductors ? How are they formed ?

What are ergastic substances? How are they formed?

What are cathode rays? How are these rays formed?

What types of semi-conductors will be formed when silicon is doped with Indium ?

What is a rainbow ? What is its two types ? How are they formed ? Discuss briefly.

What are stalagmites and stalactites? How are they formed ?

With reference to semi-conductors answer the following What is the change in the resistance of the semi-conductor with increase in temperature?

With reference to semi-conductors answer the following What is meant by doping?

With reference to semi-conductors answer the following Name the majority charge carriers in n-type semi-conductor

An n-type semi- conductor is