LM324 gives constant output even if no input is present

What do you mean with "no input"? In the schematic, both inputs are connected, and the 10 kΩ resistor will generate a higher voltage drop. And without negative feedback, you have a comparator, and 3.36 V is a plausible output (the LM324 does not have rail-to-rail outputs).

What did you expect to happen? What is the problem you're trying to solve?

I'm trying to compare 2 voltage level, on Non-Inv i want to give upto 2V and Inv is grounded. So what I'm trying to achieve is whenever Non-Inv terminal has some voltage on it, output should give high, otherwise it should give zero

You should probably use a comparator then, or at least a RRout op amp. Some listed here, 

Hi Ramee,

are you perhaps looking for a zero-crossing detector, like this?

Take the LM393 for this, but not the LM324 

Kai