{"knowledge_schema": {"broad_category": "Physics \u2192 Electromagnetism \u2192 Magnetic Circuits", "refinement": "This problem involves analyzing the work done by a current source in a magnetic circuit with a movable magnetic block and an air gap.", "specific_scope": "The focus is on calculating the work done during a rectangular cycle of current and position changes in a magnetic system with defined parameters.", "goal": "Determine the expression for the work done by the current source over one complete cycle of operation."}, "summary": "This problem is centered on the work done by a current source in a magnetic circuit involving a movable magnetic block and an air gap. The analysis requires understanding the relationship between current, magnetic fields, and mechanical movement. The work done is calculated over a rectangular cycle where the current and position of the block change in a specific sequence. The goal is to derive the correct expression for the work done by the current source during this cycle."}