Dedutions under section 24(b)

My wife, who is working, owns a property in her name and has been claiming deductions under 24 (b).

I have purchased a flat in joint name with my wife.  I pay the EMIs for it.

Owing to job compulsions both the houses are vacant..

Now Can I claim deductions under section 24(b)? If yes how much ? Can my wife also claim deductions for this new property or she should continue claiming against the property  for which she is paying EMIs? Can i claim against 80C also.

Regards

Rajeev