Units in Electronics Trivia Quiz

Answer: Ohm

Although the Greek letter omega, Ω, is used as its symbol, the unit itself is named after German physicist Georg Simon Ohm (1789-1854). Ohm found a proportionality between the voltage applied across a conductor and the resulting electric current. This relationship is known as Ohm's law (V=I*R), perhaps the most important and well-known relationship in electronics.

Answer: Farad

Capacitance is the ability to store an electrical charge. The farad is named after the English physicist Michael Faraday (1791-1867) who worked with magnetism and chemistry. The actual values in a practical circuit are typically much smaller than a farad. For example, microfarads (10^-6 farad) and picofarads (10^-12 farad) are much more common.

Answer: Henry

The henry is named after Joseph Henry (1797-1878), an American scientist who served as the first Secretary of the Smithsonian. The letter "L" is used to identify an inductor in a circuit diagram in honor of the physicist Heinrich Lenz. One henry is the amount of inductance that causes a voltage of one volt, when the current is changing at a rate of one ampere per second.

Answer: Volt

No, the volt is not named after Voltaire (the French philosopher) but much more fittingly, after Alessandro Volta (1745-1827), the Italian physicist and inventor of the electric battery.

Answer: Ampere

Electric current is the flow of electric charge. The ampere (often shortened to "amp"), is the base unit of current and named after French mathematician and physicist, Andre-Marie Ampere (1775-1836).

Answer: Watt

The unit for power is the watt, named after Scottish inventor James Watt (1736-1819) who greatly improved upon the steam engine which was fundamental in the Industrial Revolution.

Answer: Decibel

The unit, bel, is named after Alexander Graham Bell (1847-1922), the Scottish-American inventor. Since the bel is a rather large ratio, the decibel, one-tenth of a bel, is far more commonly used. The decibel (or bel) is actually a ratio and can be used to specify, for example, the power gain of an amplifier, or the power loss in a cable.

Answer: Joule

Energy is the amount of power provided for a time period. Homeowners in the US would measure their energy use in kilowatt-hours (kWh)- that's 1000 watts of power (say, ten, 100W light bulbs) for one hour. The joule, however, is less commonly used, outside of engineering at least, and is named after English physicist James Prescott Joule (1818-1889).

It is defined as the heat energy of one ampere passing through one ohm for one second. One kWh equals 3.6x10^6 joules. The joule is also used in mechanical engineering defined as the energy of one newton acting on an object through a distance of one meter (or 1 newton-meter or Nm).

Answer: Coulomb

Less commonly used, perhaps, than the other units in this quiz, the coulomb is named after French physicist Charles-Augustin de Coulomb (1736-1806). An electron, for example, has a charge of -1.6*10^-19 coulombs. An ampere is one coulomb of charge per second flowing in a cable, so that's 6.25 million million million electrons per second.

Answer: Hertz

Historically called "cycles per second", the unit of frequency was renamed during the early 20th century in honor of Heinrich Hertz (1857-1894), a German physicist who proved the existence of the electromagnetic waves that had been predicted earlier by James Maxwell.