Sandhya, as you have come to know from others' replies, both spellings are correct, and you can use either of them in your articles. But remember that if you choose to use either American version or British English, you should follow that style in your entire article, and not a few words in American English and a few in British English. Pick one style and use that here. Boddunan allows both styles but if you ever write for other clients, you will have to write according to their specified needs and requirements!
Yes,I am satisfied with you both words are correct but in my opinion educational and other works like Phd., doctorate all use practice word for their work and practise word is used in daily life.
some time it happens in MS-word even i had doubt that many words i will spell correctly but it shows the red skew lines indicating it as wrong.....
but now doubt cleared...
