Answer: an aqueous potassium hydroxide solution
An alkaline fuel cell is a zero-emission device whose one major component is the electrolyte. An electrolyte, on the other hand, is a solution that is able to conduct electricity. In an alkaline fuel cell. The electrolyte is an alkaline liquid, and potassium hydroxide also known as KOH is the only alkaline liquid among the choices.
Electrons are released, causing a flow of electrical current,<span>when sunlight strikes a photovoltaic cell.</span>
Because electrons are negatively charged so losing an electron leaves the atom with positive charge. <span />
Answer:
Human ears can hear sound waves that vibrate in the range from about 20 times a second (a deep rumbling noise) to about 20,000 times a second (a high-pitched whistling). (Children can generally hear higher-pitched sounds than their parents, because our ability to hear high frequencies gets worse as we get older.) Speaking more scientifically, we could say that the sounds we can perceive have a frequency ranging from 20–20,000 hertz (Hz). A hertz is a measurement of how often something vibrates and 1 Hz is equal to one vibration each second. The human voice makes sounds ranging from a few hundred hertz to a few thousand hertz.
Suppose you could somehow hit a drum-skin so often that it vibrated more than 20,000 times per second. You might be able to see the skin vibrating (just), but you certainly couldn't hear it. No matter how hard you hit the drum, you wouldn't hear a sound. The drum would still be transmitting sound waves, but your ears wouldn't be able to recognize them. Bats, dogs, dolphins, and moths might well hear them, however. Sounds this like, with frequencies beyond the range of human hearing, are examples of ultrasound.
Infrasonics, vibrational or stress waves in elastic media, having a frequency below those of sound waves that can be detected by the human ear—i.e., below 20 hertz. The range of frequencies extends down to geologic vibrations that complete one cycle in 100 seconds or longer.
<span>Water is not a very good solvent. FALSE</span>
