Get window handle of a particular web page

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C#

console

I want to get the window handle of a particular webpage
My code is as follows:

ProcessStartInfo psi = new ProcessStartInfo("iexplore.exe", "http://google.com");
Process p = Process.Start(psi);
int number = p.Id;
Console.WriteLine(number);//the process id
IntPtr windowHandle = p.Handle;
Console.WriteLine(windowHandle.ToInt32());// corresponding handler

I am getting a 4 digit handler. But not sure if it's correct or not. Because the process id which is returning, I can't find that process id when I am checking process ids by Task Manager.
And also I am using that window handle later to activate that page. But sometime it is not activating that page. Instead it activating some other window.
What changes I need to in my code or is there any other way by which I can get the handler of any webpage