Answer the following question given this paragraph: 

The name electric current is the name given to the phenomenon that occurs when an electric field moves down a wire at close to the speed of light. Voltage is the electrical energy density that causes the electric current. Resistance is the amount a device in the wire resists the flow of current by converting electrical energy into other forms of energy. A device, the resistor, could be a light bulb, transferring electrical energy into heat and light or an electric motor that converts electric energy into mechanical energy. The difference in Voltage across a resistor or other electrical device is called the voltage drop.


Q: What is the difference in voltage across a resistor or other electrical devices called?

 Choices:

- volt effect

- falling voltage

- power drop

- voltage drop

A:
voltage drop
