Hey Manik!

Your question is a bit unclear. It is not clear in what reference you are asking this question. If you're looking for an answer to a question asked in any of the textbooks, then you will have to mention it.  You will need to rephrase your question a bit or modify it or add more information in your question so that it is understandable and can be answered accordingly. You may write in the comment section or you may also repost your question with required adequate details so that your query can be cleared.