What Willl Happen if I Entered a Wrong Detail('1' Alphabet Wrong in my Parents Name) in My Application and I didn't notice until after the release of admit card and the correction facility is closed ?

Yes you can check application here

https://collegedunia.com/exams/jee-main/application-process

also here (https://collegedunia.com/exams/jee-main/application-process)

Hello
If you have made a mistake un spelling of your parents name then i don't think it will create a huge problem. You can tell them when they ask, usually your name and your date of birth, education records must be clear. But mistake in your parents name that too spelling error will not make problem for you. And even the correction window is closed and admit card is released then you can do nothing, be free and concentrate on your exam.