Why are multiple action potentials generated in response to a long stimulus that is above threshold?

Solution: The rapid rise and fall in the membrane potential across a cell's membrane is known as action potential. The generation of the action potential is necessary for the transfer of the nerve impulses across the neurons. The nerve impulses are generated only when the cell membrane is depolarized to its threshold level. These potentials are generate din response to different stimuli. When this stimulus is long, the recovery time is increased and the action potentials are allowed to occur after the relative refractory period above the threshold. (A refractory period can be defined as the time during which no action potential can be generated.)

This causes the generation of the multiple action potentials.