The Big Bang Theory Season 4 Episode 7 (The Big Bang Theory s04e07) with title “The Apology Insufficiency” aired on Thursday, November 4th 2010 at 08:00 pm via CBS Network.
Here is summary for The Big Bang Theory Season 4 Episode 7 :

An FBI agent interviews everyone when Howard needs to obtain a security clearance. Sheldon is beside himself when Howard refuses to accept his apology.