Misc: Which common household gadget uses the same frequencies as radar?

Questions

History : The St. Valentine's Day massacre took place in this city.?

History : The first dog in space was named _________.?

History : The last line of this document is "Working men of all countries, unite."?

History : This F.B.I agent headed the investigation of Al Capone.?

History : This French peasant girl led the army to victories.?