How long these are to be kept ?
What is the minimum duration I have to keep the amount with peticulat MF?
Most of these funds have a minimum locking period of 3 years; however, you can withdraw your amount at the end of 1 or 2 years, where you will be charged with 'Exit Load'. For further reference you can see this link below:
http://www.moneycontrol.com/india/mutualfunds/mfinfo/11/15/sn apshot/imdesc/Principal%20Personal%20Tax%20Saver%20Fund/ffdesc/Pr incipal%20%20PNB%20Asset%20Management%20Company%20Pvt.%20Ltd./imi d/MSF023/imffid/ID