Current is the rate at which electric charge passes a point in a circuit, and it’s measured in amperes. We use the convention that current is the flow of positive charges, so the direction is defined as if positive charges move through the circuit. In metal conductors the actual charge carriers are electrons (negative charges) that move opposite to this direction, but the conventional current direction stays the same to keep analysis consistent. One ampere equals one coulomb per second, so current tells you how much charge flows each second. The other descriptions mix up concepts: flow of negative charge refers to electron movement rather than the conventional current direction; resistance is the property that opposes current and is measured in ohms; power is measured in watts and describes energy transfer, not the flow itself.

A lathe. In turning, the workpiece rotates while a single-point cutting tool feeds in a straight line, producing a linear cut path along the length of the part and forming a cylindrical surface. This combination of rotational workpiece motion with linear advancement of a single-point tool is the hallmark of turning on a lathe. A drill press is used for holes with a rotating drill, not a single-point tool creating a linear surface path; milling uses multi-point cutters and multi-axis motion for more complex paths; and a milling machine with multiple axes isn’t described by a single-point, linear-cut setup.

The connector that links the equipment to the AC power source is the AC plug. The plug is the male connector at the end of the power cord that you insert into a wall outlet, which is the socket or receptacle. This arrangement allows the electrical current to flow from the AC source into the device. The other options serve different roles: a switch simply opens or closes the circuit, and a fuse provides protection by interrupting current in faults.

Capacitance describes how much electric charge a capacitor can store for a given applied voltage. It is defined by the relation C = Q/V, meaning the charge stored scales linearly with the voltage across the plates, with the ratio Q/V staying constant for a capacitor with a fixed capacitance. The energy stored in a capacitor is E = 1/2 C V^2, so energy per volt isn’t a fixed property of the capacitor and depends on the voltage itself. The idea in one option about a battery’s total charge relates to a source’s capacity, not a capacitor’s ability to hold charge per volt. The other ideas—resistance to current flow and electromotive force—describe different electrical properties. So the defining concept is that capacitance is the charge stored per unit voltage, Q per V.