Every one should tell me that , is bitcoin is a good currency system or has some disadvantages. as I am new to it and come to know that there is very high fluctuation in its price.So give me the advice how much risk in getting paid in btc or $.
Bitcoin can be good and still maintain some disadvantages, the two are not mutually exclusive.
You're right, there is a lot of fluctuation in price, but the number of bitcoins you hold will not fluctuate, unless you trade. I know a few people that believe in holding coins and so far they are proving to be doing quite well.
Personally I wouldn't risk being paid in bitcoins, least not my whole wage. I always have the option to go out and buy bitcoins with my existing wage.