The April 11 debate between Sen. Richard Lugar, R-Ind., and GOP primary-election challenger Richard Mourdock will be broadcast at 7 p.m., the Indiana Debate Commission announced Tuesday.

The commission said voters can submit questions for the candidates on Facebook or at the panel's website.

The campaigns signed a document on the debate's format and rules Tuesday at WFYI Public Media in Indianapolis, the site of the hour-long debate, according to a statement by the commission. The TV station will broadcast the debate and make it available for other news organizations to carry.

There will not be a studio audience for the debate.

The commission said Phil Bremen will be the moderator. Bremen is a retired TV broadcaster who teaches at Ball State University.

Questions for Lugar and Mourdock, the state treasurer, can be submitted at www.facebook.com/IndianaDebateCommission or at http://indianadebatecommission/submit-your-debate-question/.

The commission said people who submit questions chosen for consideration will be offered the chance to ask them in person or by pre-taped video.