Bind resolving other nameservers

[Steve Job]

I need a little clarification in this.

If I had my domain set at my registrar to use:
ns1.mydomain.com
ns2.mydomain.com


ns1.mydomain.com is running Bind and is working perfectly.

ns2.mydomain.com is running Bind but it has not been configured as a slave yet.


Will users receive DNS errors?  Will all requests just go to
ns1?  Or will all requests goto ns1 only if ns2 is unreachable or
does not have Bind running.

Thanks for some help.
-Steve