What is the unit of electromotive force represented by the symbol V?

The unit of electromotive force denoted by the symbol V is the Volt. The Volt is defined as the potential difference that will drive one ampere of current against one ohm of resistance. In simpler terms, if you imagine a circuit, the Volt measures how much energy is supplied per unit charge. This energy is crucial for the movement of electric charges through a circuit, and it forms the basis of many electrical concepts and applications.

Understanding this, the other options represent different electrical measurements that do not directly pertain to electromotive force. The Ohm is the unit of resistance, the Ampere is the unit of electric current, and the Watt is the unit of power. Each of these plays a critical role in electrical theory but does not describe electromotive force specifically. Thus, the Volt stands out as the correct unit associated with this concept.