1. Is it necessary to have promisory note or only cheque is sufficient
The cheques are valid for 6 months, and Promissory Note can be of any duration. The promissor note will strenghthen your claim for repayment of laon. You must get a promissory note from him as a better security.
2. If promisory note is necessary is it required to be printed on a stamp paper. If yes what value of stamp paper is required ;
There is usually availble with stam paper vendors the non judicail paper- in hindi it is called; HUNDI .However you can print or write on a paper and start the wording as "on demand i promise to pay to....such and suhch amont and give full details of transaction.
Banks even make witnesses to sign the DP note .
3. I dont have transaction reference to claim
That is secondry part. If asked you need to show that where from you have the money ;savings from your income , sold any thing, etc.
4 lac, only 50k i have done a bank transfer. will the case have grounds at court?
You must make a DP note for that to show that you paid the cash as well as transferred the money by transaction dated....
Secure your money properly.