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This energy trivia quiz has 50 free questions with answers and runs from the physics classroom to the power plant. It covers the units (joule, watt, horsepower, kilowatt-hour, calorie), the laws of thermodynamics, kinetic and potential energy, and the men who named them, then moves through the history of how we make power: Volta's pile, Faraday's dynamo, Edison's Pearl Street station and the war of the currents, the first oil well, the first wind turbines and solar cells, Fermi's pile under a football stadium, and the first nuclear plant to feed a grid. The easy questions ask what unit your electricity bill uses, what the Sun runs on and where Hoover Dam is. The medium ones cover the 1973 oil embargo, Chernobyl and Fukushima, the world's biggest power station and the countries that run almost entirely on geothermal, wind or nuclear power. The hard ones want the depth of the Drake Well, the voltage of an electric eel, ITER's power target and the oldest Nobel laureate in history. Every answer has been checked against a reference encyclopaedia, and each question shows its explanation and citation once you have answered.
30 of 50 questions with answers and explanations. Play the quiz
Q 01The SI unit of energy is named after which English physicist?
James Prescott Joule
One joule is the work done when a force of one newton moves something one metre; a joule of energy will lift a small apple about a metre.
Q 02The term 'horsepower' was adopted in the late 18th century by which engineer to sell his steam engines?
James Watt
He needed a figure customers could picture: how many draft horses an engine replaced. One imperial horsepower is about 745.7 watts.
Q 03In which year did Einstein publish the paper establishing mass-energy equivalence, E = mc²?
1905
It was one of his four 'miracle year' papers; the paper actually says a body giving off energy L loses mass L/c², rather than writing the famous formula.
Q 04In which city was Edison's Pearl Street Station, the first US commercial central power plant, opened in 1882?
New York
On its first day it powered just 400 lamps for 82 customers in lower Manhattan; two years later it served 508 customers and more than 10,000 lamps.
Q 05The world's first nuclear power plant to feed electricity into a grid, in 1954, was in which country?
Soviet Union
Obninsk, about 110 km from Moscow, produced only about 5 megawatts of net electricity, but it ran until 2002.
Q 06The world's largest power station by installed capacity, at 22,500 megawatts, sits on which river?
Yangtze
China's Three Gorges Dam displaced more than a million people and slightly slowed the Earth's rotation by shifting so much water uphill.
Q 07The Chernobyl explosion of 26 April 1986 happened in which of the plant's four reactors?
Unit 4
It blew up during a test simulating how the reactor's cooling would behave in a blackout; the other reactors kept running for years, the last closing in 2000.
Q 08Besides Chernobyl, which nuclear accident was rated level 7 on the International Nuclear Event Scale?
Fukushima Daiichi (2011)
Fukushima was triggered by the Tōhoku earthquake and a tsunami up to 14 metres high that knocked out cooling for the emergency diesel generators.
Q 09During the 1973 oil embargo, the price of a barrel of oil rose from about $3 to nearly what?
$12
Arab exporters cut off countries that had backed Israel in the Yom Kippur War, a rise of nearly 300 percent that brought petrol rationing and 55 mph speed limits to the US.
Q 10The first commercial oil well in the United States, drilled by Edwin Drake in 1859, is in which state?
Pennsylvania
The well beside Oil Creek near Titusville was only 69.5 feet deep, but it set off the first American oil boom.
Q 11How deep was Edwin Drake's pioneering 1859 oil well?
About 70 feet
Modern wells routinely go down several kilometres; Drake's success mattered because it prompted enough drilling nearby to supply real businesses.
Q 12The first continuous-current battery, built around 1800, stacked zinc and copper discs with cloth soaked in what?
Brine
Alessandro Volta's pile gave the world the volt; he had been arguing with Luigi Galvani about whether frogs' legs twitched from 'animal electricity'.
Q 13John B. Goodenough became the oldest Nobel laureate at 97 by sharing the 2019 chemistry prize for what?
Lithium-ion batteries
Q 21Who first demonstrated the photovoltaic effect in 1839, aged 19, in his father's laboratory?
Edmond Becquerel
His son Henri would later share a Nobel Prize with the Curies for discovering radioactivity; the family produced four generations of physicists.
Q 22The first practical silicon solar cell was publicly demonstrated in 1954 at which research institution?
Bell Laboratories
Calvin Fuller, Daryl Chapin and Gerald Pearson's cell was far more efficient than Charles Fritts's 1883 selenium device, which converted about 1 percent of sunlight.
Q 23In which country did James Blyth build a wind-powered machine to light his holiday home in July 1887?
Scotland
He shared it with Stanley Whittingham and Akira Yoshino; his cobalt-oxide cathode from 1980 is still the basis of the battery in most phones.
Q 14Roughly what voltage can a South American electric eel deliver in a single shock?
Up to 860 volts
Despite the name they are knifefish, not true eels, and they use weaker pulses as a kind of radar to navigate murky water.
Q 15How much fusion heat is ITER designed to produce from 50 megawatts of input?
500 MW
That tenfold gain would run for pulses of 400 to 600 seconds; the whole site needs more than 300 MW of electricity to make it happen.
Q 16Roughly how much hydrogen does the Sun's core fuse into helium every second?
600 billion kg
About four million tonnes of that mass becomes pure energy each second; the light produced takes 8 minutes 19 seconds to reach Earth.
Q 17How long does light from the Sun take to reach Earth?
About 8 minutes
8 minutes 19 seconds at the average distance; 1.3 seconds is the trip from the Moon, and 4 hours gets you to Neptune.
Q 18The 'Calorie' on a US food label is really a kilocalorie. How many small calories is that?
1,000
A small calorie heats one millilitre of water by one degree Celsius and equals exactly 4.184 joules, so a 200-Calorie snack is about 837 kilojoules.
Q 19One thermochemical calorie is defined as exactly how many joules?
4.184
The definition rests on the energy needed to warm a millilitre of water by one degree Celsius; the other numbers are the electron charge, gravity and Avogadro's number in disguise.
Q 20In which country are at least 90 percent of homes heated with geothermal energy?
Iceland
Sitting on the Mid-Atlantic Ridge helps; in 2020, 99.94 percent of the country's electricity came from hydro and geothermal sources.
Blyth offered surplus power to light the main street of Marykirk, but locals refused it as 'the work of the devil'; Charles Brush built a larger automatic turbine in Cleveland months later.
Q 24The first artificial nuclear reactor went critical in 1942 under a football stadium at the university of which city?
Chicago
Enrico Fermi's team built Chicago Pile-1 under the west stands of Stagg Field; the leaders trusted his calculations enough to run it in the middle of a city.
Q 25Hoover Dam impounds Lake Mead on the border between Nevada and which other state?
Arizona
Built between 1931 and 1936 in the Black Canyon of the Colorado River, it was called Boulder Dam by the Roosevelt administration until Congress restored Hoover's name in 1947.
Q 26Which pigment do plants mainly use to capture light for photosynthesis?
Chlorophyll
Carbon dioxide and water plus photons become carbohydrate and oxygen, which is where every calorie in your food and nearly all of the air you breathe comes from.
Q 27Which law of thermodynamics says energy can be transformed but neither created nor destroyed?
The first law
The second law says entropy in an isolated system never decreases, and the third says entropy approaches a constant as temperature approaches absolute zero.
Q 28Under the third law of thermodynamics, a system's entropy approaches a constant value as what approaches zero?
Its temperature
Absolute zero itself, -273.15 °C, cannot be reached in a finite number of steps, which is why the coldest labs get within billionths of a degree and no closer.
Q 29In the 1880s 'war of the currents', which company's AC system did Edison's DC oppose?
Westinghouse
Westinghouse underbid GE to light the 1893 World's Columbian Exposition in Chicago, a showcase that won it the contract for the Niagara Falls power station.
Q 30The kilowatt-hour on your electricity bill equals how many megajoules?
3.6
A kilowatt for an hour is 1,000 joules per second times 3,600 seconds; utilities bill in kWh because it maps neatly onto appliances rated in watts.