Electricity and Magnetism
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50 free Electricity and Magnetism trivia questions with answers — science & nature quiz, new questions added Oct 2026.
Electricity and magnetism look like two separate things: one makes sparks jump and lights glow, the other makes a compass needle swing north. In the nineteenth century a handful of experimenters showed that they are two faces of a single force, and almost every piece of modern technology, from power grids to hospital scanners, grew out of that discovery. This multiple-choice quiz covers the whole story. You will meet the basics taught in school science, such as static charge, conductors, circuits, magnetic poles and field lines, alongside the scientists who gave their names to the units, the inventions that put the theory to work, and the places where electromagnetism turns up in nature, from thunderstorms to animals that sense or produce electric fields. The questions range from easy to challenging, so the quiz suits middle school students revising a science topic as well as adults who want to test what they remember from physics class. Every answer comes with a short explanation, so you learn something even when you guess wrong.
30 of 50 questions with answers and explanations. Play the quiz
Q 01Luigi Galvani's 1780s discovery of "animal electricity" came when sparks made the severed legs of which animals twitch?
Frogs
Frogs twitching on his bench convinced Galvani that animals run on electricity, and talk of such "galvanism" helped inspire Mary Shelley's Frankenstein.
Q 02The word "electricity" comes from the Greek name for which material, which attracts light objects after being rubbed?
Amber
Amber is "elektron" in Greek, and people around the ancient Mediterranean knew that a rod of it rubbed with cat's fur would pull in feathers.
Q 03Which 18th-century experimenter borrowed a military term to call his linked set of electrical capacitors a "battery"?
Benjamin Franklin
Benjamin Franklin took the word in 1749 from the military term for weapons working together, and later proposed flying a kite in a storm to show that lightning is electrical.
Q 04In the War of the Currents, Thomas Edison campaigned against which electrical system promoted by George Westinghouse?
Alternating current
Alternating current was painted as deadly by Edison's allies, who killed stray dogs with it at public demonstrations, yet it became the standard for power grids.
Q 05Which layer of Earth, a churning mix of molten iron and nickel, generates the global magnetic field?
The outer core
The outer core is stirred by heat escaping from the planet's centre, and the field inside it is about 50 times stronger than the one felt at the surface.
Q 06Rubbing a balloon on your hair leaves the balloon negatively charged because it has picked up extra what?
Electrons
Electrons move from the hair to the balloon, leaving every strand positively charged, which is why the hairs push apart and stand on end.
Q 07Which precious metal is the best electrical conductor of all, narrowly beating the copper used in household wiring?
Silver
Silver conducts electricity better than any other metal, but its high cost means it is rarely used for that, leaving copper to wire the world.
Q 08Old-style Christmas tree lights all went dark when a single bulb failed because they were wired in which arrangement?
A series circuit
A series circuit gives the current only one path, so a single dead bulb breaks the whole loop until the faulty one is found and replaced.
Q 09Which device lets a scrapyard crane lift a load of scrap steel and then release it at the flick of a switch?
An electromagnet
An electromagnet is magnetic only while current flows through its coil; the first one, built in 1824, weighed seven ounces yet lifted nine pounds.
Q 10Which Art Deco skyscraper, for decades the world's tallest, is struck by lightning about two dozen times a year?
Empire State Building
The Empire State Building is topped with a lightning rod, and tall grounded structures like it concentrate the electric field beneath a thundercloud.
Q 11Which English former bookbinder's apprentice, largely self-taught, discovered electromagnetic induction in 1831?
Michael Faraday
Michael Faraday wrapped two coils of wire around an iron ring and found that starting a current in one made a momentary current flow in the other.
Q 12Which naturally magnetised rock was suspended so it could turn, making the first magnetic compasses for navigators?
Lodestone
Lodestone means "leading stone" in Middle English, and it is one of only a very few minerals found naturally magnetised.
Q 13Which sky display, seen mostly near the poles, is caused by charged particles from the Sun striking the atmosphere?
The aurora
Q 21Which Scottish physicist's equations of the 1860s showed that light is a wave of electric and magnetic fields?
James Clerk Maxwell
James Clerk Maxwell also predicted radio waves from the same theory, and separately worked out that Saturn's rings must be made of numerous small particles.
Q 22Which inventor, namesake of the SI unit of magnetic flux density, quit Thomas Edison's company after only six months?
Nikola Tesla
Nikola Tesla left the Edison Machine Works to strike out on his own, and his work had slipped into relative obscurity before the unit was named in his honour in 1960.
Q 23Which unit of energy, equal to 3.6 million joules, do electricity companies use to bill household customers?
The aurora takes its name from the Roman goddess of dawn, and Earth's magnetic field is what steers the incoming particles towards the polar regions.
Q 14Which planet's magnetic field is the most powerful in the Solar System, with a tail reaching almost to Saturn's orbit?
Jupiter
Jupiter has a magnetic field about 20 times stronger than Earth's, and if its magnetosphere were visible it would look five times wider than the full Moon.
Q 15Which metal, the least dense of all, is used in the rechargeable batteries honoured by a 2019 Nobel Prize?
Lithium
Lithium is light enough to float on water, and the batteries built around it made mobile phones, laptops and electric cars practical.
Q 16Which safety device protects a circuit with a thin wire designed to melt when too much current flows?
A fuse
A fuse is a sacrificial device that must be replaced once its wire has melted, one reason circuit breakers have taken its place in many settings.
Q 17Sprinkling which powder on a sheet of paper laid over a bar magnet reveals the curved lines of its magnetic field?
Iron filings
Iron filings line up along the direction of the field, but the neat gaps between their lines are made by the filings themselves, because the real field is continuous.
Q 18Which American portrait painter turned inventor opened a telegraph line in 1844 with the words "What hath God wrought"?
Samuel Morse
Samuel Morse had already made his name painting portraits when, in middle age, he helped develop a telegraph that needed only a single wire.
Q 19Which office machine, born of Chester Carlson's 1930s kitchen experiments, uses static charge to stick toner to paper?
Photocopier
The photocopier uses xerography, a dry process devised by a patent attorney who found copying documents by hand painful and tedious.
Q 20Which eerie blue glow on ships' masts during thunderstorms did sailors sometimes welcome as a good omen?
St. Elmo's fire
St. Elmo's fire, named after the patron saint of sailors, is plasma that forms when a strong electric field makes the air glow around a pointed object.
Kilowatt-hour
A kilowatt-hour is the energy a one-kilowatt appliance uses in an hour, and a typical home gets through a few hundred to a few thousand of them a month.
Q 24What name is given to materials such as glass, rubber and most plastics that do not let electric current flow freely?
Insulators
Insulators such as glass and paper have very high resistivity, which is why the wires inside a cable are wrapped in plastic instead of being left bare.
Q 25Which device changes the voltage of mains electricity, stepping it down between power lines and household sockets?
A transformer
A transformer works by induction: a varying current in one coil creates a changing magnetic flux, which induces a voltage in a second coil wound alongside it.
Q 26Which machine inside fans, drills and washing machines uses magnetic fields to turn electrical energy into rotation?
A motor
A motor can also run in reverse: electric cars spin theirs while braking to recover energy that would otherwise be lost as heat and friction.
Q 27Which machine, a favourite of science classrooms, uses a moving belt to build up charge on a hollow metal terminal?
Van de Graaff generator
The Van de Graaff generator began in 1929 as a tin can and a silk ribbon, and an inexpensive tabletop version can still produce around 100,000 volts.
Q 28Passing an electric current through water, first done with a battery in 1800, splits it into oxygen and which gas?
Hydrogen
Hydrogen bubbles off in twice the amount of the oxygen, matching the two-to-one ratio in water's formula, H2O.
Q 29The ampullae of Lorenzini, jelly-filled pores that sense the electric fields of prey, are found on which predators?
Sharks
Sharks have the pores clustered around the snout and mouth, where they pick up the weak electrical signals given off by a prey animal's muscle contractions.
Q 30The magnetic compass was first made as a fortune-telling device about 2,000 years ago in which country?
China
China used the compass for divination from the Han dynasty and only turned it to navigation in the 11th century, more than a thousand years later.