1. The question "at which point do we assume V" is unclear without context. 2. Typically, in physics or engineering, $V$ often represents voltage or potential, and the point at which $V$ is assumed or measured depends on the problem setup. 3. For example, in circuit analysis, $V$ might be assumed at a node or reference point. 4. Please provide more details or context about $V$ so I can assist you better.