Questions

The Quality Factor is also defined, as Q. So it is a number, which reflects the lossness of a circuit. higher the Q, the lower are the losses.

the quality factor is measurement of efficiency (or effectiveness) of a device or circuitry. In literal sense quality factor means qualitative performance of a device.

The Article - I of the constitution of India describes India as Union of States.

Resistivity :

Resistivity is a measure of the resistance to the flow of electrons. 

Conductivity :

Conductivity is just the inverse of resistivity, σ = 1/ρ, where σ is conductivity and ρ is resistivity.

Example:

Think of a pipe and water, the bigger the pipe, the easier water can flow and thus the lower the resistance. 

The 828-metre (2,717 ft) tall Burj Khalifa in Dubai has been the tallest building since 2008.

A primary key is a special relational database table column or combination of columns designated to uniquely identify all table records. That is, A primary key is a column or set of columns in a table that uniquely identifies tuples (rows) in that table.

A primary key, also called a Primary Keyword.

Main Features Primary key are ::

It must contain a unique value for each row of data.

It cannot contain null values.