PHYSICAL SETTING PHYSICS - JMAP

the siren on top of a firehouse. Compared to the frequency produced by the siren, the frequency observed by a firefighter approaching the fire-house is (1) lower (2) higher (3) the same 31 White light is passed through a cloud of cool hydrogen gas and then examined with a spectro-scope. The dark lines observed on a bright back-ground are caused by

  House, Fire, Firehouse, Fire house