Explain the difference between an equilibrium level of GDP and a level of GDP which is in disequilibrium.

What will be an ideal response?

If GDP is not in equilibrium, then aggregate expenditures will exceed real GDP or vice versa. If aggregate expenditures exceed real GDP, then businesses will find their inventories reduced below the planned level of inventories. Businesses will therefore expand production to replenish inventories and the economy will not be in equilibrium until the level of planned inventories is met.
On the other hand, if real GDP exceeds aggregate expenditures, then business inventories will be above the level planned. In order to bring inventories down to their planned level, production and output will be reduced until the real GDP is equal to planned aggregate expenditures.