Final answer:
Expansionary monetary policy by the Federal Reserve leads to an increase in aggregate demand, a rise in real GDP and the price level, and a depreciation of the currency which boosts net exports in an open economy.
Step-by-step explanation:
When the Federal Reserve decides to buy bonds to increase the money supply, it is engaging in expansionary monetary policy. This leads to multiple effects in an open economy: First, the aggregate demand will increase, causing both real GDP and the price level to rise. In an open economy, this also affects interest rates and exchange rates.
As the Fed buys bonds, the demand for bonds rises and their prices increase, which in turn reduces the interest rate. A lower interest rate makes American securities less attractive to foreign investors, leading to a decrease in the demand for the US dollar, thus depreciating the currency.
This currency depreciation further increases aggregate demand because it makes American goods cheaper overseas and fuels an increase in net exports. Consequently, the aggregate demand curve shifts to the right, stimulating economic growth and potentially closing any recessionary gap.