The Red-belly snake (Storeria occipitomaculata) is a relatively small snake that rarely exceeds 12 inches in length. It is native to North America, Mexico and Central America, and it is NOT venomous.
The electromagnetic frequency of a wave is defined as how many times the peak of this oscillation moves past a point each second. This has a major effect on the properties of the wave, including its energy.
Electromotive force, also called emf (denoted $\mathcal{E}$ and measured in volts), is the voltage developed by any source of electrical energy such as a battery or dynamo. Which means that all EMF are voltages but not all voltages are EMF. A voltage is only an EMF if it is a source of energy.