NO.PZ2022071403000058
问题如下：
Question
If the central bank buys securities from banks in its open-market operations when the economy is already in long-run equilibrium, which of the following is most likely to occur?
选项：
A.The aggregate demand curve will shift to the left. B.The long-run supply curve will be unaffected, but the price level will rise. C.Both the long- and the short-run aggregate supply curves will shift to the right.解释：
SolutionB is correct. When the central bank buys securities from banks in an open-market operation, it pays for them with a corresponding increase in bank reserves. This increases the amount of deposits banks can accept from their customers—that is, the money supply. An expansionary monetary policy will cause the aggregate demand curve to shift to the right. The short-run supply curve will also shift to the right because input prices do not initially adjust upward. In time, prices will increase, causing the short-run aggregate supply curve to steepen and eventually return to the long-run natural level of output—but at higher prices.
A is incorrect. The purchase of securities by the central bank results in an increase in money supply, which will result in lower interest rates, higher investment, and possibly higher consumption, causing the aggregate demand curve to shift to the right.
C is incorrect. The purchase of securities by the central bank results in an increase in money supply. Initially, the short-run aggregate supply curve will shift to the right because prices are fixed, but as prices rise, output will return to its long-run natural level, leaving the long-run supply curve unchanged.
The short-run supply curve will also shift to the right because input prices do not initially adjust upward.
为什么short-run supply curve shift to the right?
In time, prices will increase, causing the short-run aggregate supply curve to steepen and eventually return to the long-run natural level of output—but at higher prices.
价格上涨为什么会导致short-run aggregate supply crve steepen?为什么会最终回归到long-run natural output at higher prices
