BSE India (Sensex 30) and NSE India (NIFTY 50). What are they ?

What is Sensex 30 and NIFTY 50 ?
I know I am acting stupid by writing such kind of post as all of you must be familiar with this but this is for my readers from other countries.

The full form of Sensex is Sensitive Index and of NIFTY is National Fifty.
Sensex is a Benchmark index of BSE and Nifty is an Index of NSE.
Sensex 30 comprises of all major companies listed on BSE based on their market cap. and liquidity.
Some of the companies at present in SENSEX 30 are Reliance Ind., Infosys ,TCS, LNT etc.
The movement in the all 30 scripts makes a movement in Sensex i.e. it leads the sensex to go up or down.
The same is in case of NIFTY it comprises to top 50 stocks listed on NSE.
Their movement will deside index movement.

Some times we see Midcaps are positive even when Sensex is trading negative, this is because Sensex is calculated on bases of 30 stocks in it. The same is for NIFTY.

Even Sensex and Nifty various other sectoral indices such as bankex for banking, PSU for PSU companies.