If the Federal Reserve uses expansionary monetary policy, then:
there is a negative short-run effect on real GDP but prices remain unchanged in the long run.
there is a positive short-run effect on the price level but the aggregate price level remains unchanged in the long run.
there is a positive long-run effect on real GDP but GDP remains unchanged at its potential level in the short run.
there is a positive short-run effect on real GDP but GDP remains equal to potential GDP in the long run.