An interior door does not have to withstand extreme weather changes. Interior and exterior doors are not the same product sold under different labels. The construction of each is different, with exterior doors given special treatment to stand up to the elements and frequent use.
The charging of lead-acid batteries can be hazardous. However, many workers may not see it that way since it is such a common activity in many workplaces. The two primary risks are from hydrogen gas formed when the battery is being charged and the sulfuric acid in the battery fluid.
Voltages are produced by converting one form of energy into electrical energy. Mechanical energy can be converted into electrical energy (voltage and current) by moving a magnet or magnetic coil in proximity with a stationary coil, connected to an electrical circuit. A voltage can also be produced with a chemical reaction. Batteries and fuel cells convert energy in specially designed cells, where a chemical reaction causes a voltage to exist across two electrodes implanted at two different parts of the cell. A voltage can be produced by the interaction of light on a photocell. The photons of light interacting with atoms in the photocell, cause an electron to be ejected. The special design of the photocell causes this to occur in such a manner as to produce voltage across the cell. A voltage can be produced by subjecting a thermocouple to differential temperature. A thermocouple is a relatively simple device composed of two dissimilar metals, joined together at what is referred to as a thermal junction.