Final answer:
An electrosurgical unit utilizes high-frequency electrical currents to perform surgery and can be cooled by fluids. The sharp edge of a scalpel is where most current flows due to the 'point effect.' High-frequency AC is used for precision and safety.
Step-by-step explanation:
The machine that uses electric impulses to generate heat and potentially can be cooled by air or fluid flowing through the power cord is an electrosurgical unit. These units utilize high-frequency electrical currents to cut tissue, coagulate blood vessels, or otherwise perform surgical procedures. The electric impulses generate localized heat, and often the device is designed to minimize patient burns by using a cooling system that could involve fluid flowing through the cord. Electrosurgical units often use high-frequency AC to minimize the stimulation of muscles and nerves, which is preferable for precise surgical procedures.
Given the context of surgery with a high-voltage electric scalpel, it can be noted that most of the current is expected to flow from the sharp edge of the scalpel due to the electric field being more intense at pointed objects or sharp edges - a concept known as the 'point effect' in physics. Additionally, high-frequency AC is typically used in electrosurgical units to ensure precision and safety in cutting through tissues.