I have an existing website running from my IIS in asp. (for e.g. www.test.com)

Now I created one more folder in the same directory (folder1) and publish my .net website code to that folder.

Can I able to access it when I try to enter the same URL in the browser with that
newly created folder appended after it ? (for e.g www.test/folder1/). Will that directly
go to default.aspx page of folder1 ?

It should look for default.aspx in the subfolder.

You could always force it to that file when you call the folder (in a hyperlink or redirect or transfer eg www.test/folder1/default.aspx )

As with all these things the best way to learn is try it and see what works and what does not.

It can find the Default.aspx in the subfolder