Answer
The IUPAC name of the alkene is $2−ethylpent−1−ene$
Work Step by Step
The compound has 5 carbon atoms in its longest carbon chain containing the double bond ($pent−$). It has an $ethyl−$ substituent at position 2, and a double bond at position 1. So, the IUPAC name of the alkene is $2−ethylpent−1−ene$