An electric breaker or fuse acts like an emergency switch that shuts the power off when too much current is flowing. Resistance is a factor that opposes the flow of electricity. A good conductor of electricity, such as copper, has low resistance. Electrical resistance is measured in units called ohms . V stands for voltage.
R stands for resistance.
While a capital I is the symbol for current, the actual units that current is measured in are called amperes , or amps for short.