Radar Trivia
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46 free Radar trivia questions with answers — technology quiz, new questions added Oct 2026.
Radar is the wartime secret that now opens supermarket doors, catches speeders and tells you whether to carry an umbrella. This quiz covers the technology from Heinrich Hertz's bounced radio waves to over-the-horizon arrays and stealth aircraft. The easy questions ask what the acronym stands for, who coined it, which effect lets radar read speed, what a police radar gun does and why weather radars glow red. From there it moves into the invention story: Hülsmeyer's telemobiloscope, the death-ray rumour that led Watson-Watt and Wilkins to the Daventry Experiment, the Chain Home stations that helped win the Battle of Britain, and the ten-centimetre magnetron that Randall and Boot built in Birmingham. The harder end is for history and engineering readers: the Tizard Mission's deed box, the MIT Radiation Laboratory, the SCR-270 blip at Opana Point, Window over Hamburg, the Bruneval raid, the Soviet Redut sets, the first radar echoes from the Moon and Venus, Ufimtsev's diffraction paper that shaped the F-117, the Russian Woodpecker, the Arecibo dish and the Bell Labs origins of the radar altimeter, plus the letter-band code names and the range equation's inverse fourth power. Every answer was checked against encyclopaedia entries on radar, its history and its applications, and the supporting sentence is stored with each question. If you enjoy this one, try our World War II, inventions and aviation quizzes next.
30 of 46 questions with answers and explanations. Play the quiz
Q 01What does the acronym RADAR stand for?
Radio detection and ranging
RADAR stands for radio detection and ranging, a term coined in 1940; it has since become an ordinary lowercase noun.
Q 02Which German physicist showed in the 1880s that radio waves reflect off solid objects?
Heinrich Hertz
Heinrich Hertz bounced radio waves off metal surfaces in his laboratory, showing that they reflect just as light does and proving Maxwell's theory of electromagnetic waves.
Q 03Which German inventor patented the 'telemobiloscope' in 1904 to detect ships in fog?
Christian Hülsmeyer
Christian Hülsmeyer patented his telemobiloscope in 1904; it rang a bell when a ship came within range but could not measure distance, and the German navy declined it.
Q 04Which Russian physicist noted in 1897 that a passing ship disturbed radio signals?
Alexander Popov
Alexander Popov, testing ship-to-ship radio in 1897, noted that a passing vessel disturbed the signal and remarked it might detect objects, but took it no further.
Q 05Which vegetable did British wartime propaganda credit for RAF night-fighter kills that were really won by airborne radar?
Carrots
Carrots, the press was told, gave ace John 'Cat's Eyes' Cunningham his night vision; the cover story stuck, and many Britons came to believe the vegetable helped them see in the dark.
Q 06What rumoured German weapon prompted the enquiry that led Britain to radar?
A radio death ray
A radio death ray was the rumour the Air Ministry asked about; Arnold Wilkins calculated that it was impossible, then suggested using radio waves to detect aircraft instead.
Q 07Whose shortwave transmitter was used for the Daventry Experiment of 26 February 1935?
The BBC's
The BBC's shortwave transmitter at Daventry supplied the signal; a Heyford bomber flew through its beam while Arnold Wilkins's receiver, in a van parked in a field, picked up the echoes.
Q 08What did Watson-Watt reportedly exclaim after the Daventry test succeeded?
'Britain has become an island again!'
'Britain has become an island again!' was Watson-Watt's own later account of his words; within days the government had funded the work and sworn the team to secrecy.
Q 09What was the codename of Britain's ring of coastal early-warning radar stations?
Chain Home
Chain Home's stations were bombed in August 1940 but most were back on the air within hours, and the Luftwaffe, never grasping how vital they were, soon stopped attacking them.
Q 10Where in Suffolk did Britain's radar team develop its coastal warning stations from 1936?
Bawdsey Manor
Bawdsey Manor became the Air Ministry's radar research station in 1936; when war broke out in 1939 its scientists were moved to Dundee for fear of a German raid on the exposed coastal site.
Q 11Which battle did early warning from coastal radar stations help the RAF to win in 1940?
Battle of Britain
Battle of Britain pilots could be scrambled only when a raid was seen approaching, instead of flying standing patrols; that use of radar was the core of the 'Dowding system'.
Q 12Which two Birmingham physicists built the improved cavity magnetron in 1940?
John Randall and Harry Boot
John Randall and Harry Boot's device gave hundreds of watts at a 10 cm wavelength, a leap in power that let radar sets shrink enough to be carried in aircraft.
Q 13What everyday appliance later used the cavity magnetron?
The microwave oven
Q 21What was the British codename for chaff, the metal strips dropped to blind radar?
Window
Window was the British name and Düppel the German; both sides sat on the idea for over a year, each afraid the other would copy it and blind their own radar.
Q 22Over which city was the foil countermeasure first used, during Operation Gomorrah in 1943?
Hamburg
Window was first dropped over Hamburg on the night of 24-25 July 1943; German searchlights and flak radars wandered helplessly among the false echoes.
Q 23Which German radar was seized and brought to Britain in Operation Biting in 1942?
Würzburg
The Bruneval raid of February 1942 carried off key parts of a Würzburg set; examining its receiver and transmitter showed British scientists how it could be jammed.
The microwave oven grew out of radar work: in 1945 Raytheon engineer Percy Spencer is said to have noticed a magnetron melting the candy bar in his pocket.
Q 14Which 1940 British delegation carried a magnetron to the United States?
The Tizard Mission
The Tizard Mission gave the magnetron away because Britain lacked the factories to exploit it; a US historian called it 'the most valuable cargo ever brought to our shores'.
Q 15Which secret wartime US lab, organised by Alfred Loomis, turned Britain's magnetron into working radar sets?
MIT Radiation Laboratory
The MIT Radiation Laboratory took a deliberately misleading name: it was chosen to make outsiders think its scientists were doing nuclear physics, not radar.
Q 16Where on Oahu's north shore did an Army radar spot the incoming Japanese planes in 1941?
Opana Point
Opana Point's radar crew picked up the raid at 7:02 am, but Lieutenant Kermit Tyler took the blip for B-17 bombers due from the mainland and told them not to worry.
Q 17In military radar, what does the abbreviation IFF stand for?
Identification friend or foe
Identification friend or foe uses a transponder that answers a radar's interrogation signal; it was developed in the Second World War after radar arrived and friendly-fire incidents followed.
Q 18Which German warship carried an early Seetakt radar when she was scuttled off Montevideo in 1939?
Admiral Graf Spee
Admiral Graf Spee settled in shallow water after the Battle of the River Plate, leaving the aerial of her radar set standing in plain view above the surface.
Q 19Which Cold War radar network stretched across the Arctic from Alaska to Greenland to watch for Soviet bombers?
The DEW Line
The DEW Line, short for Distant Early Warning, was finished in 1957 to spot bombers, but it could not see the ballistic missiles that soon became the greater threat.
Q 20Which ocean liner had parts of a French obstacle-detecting radio set installed in 1935?
Normandie
Normandie's detector, an early form of radar, could not save her from a different danger: in 1942 she caught fire and capsized at her New York pier while being converted into a troopship.
Q 24What phenomenon lets radar read a target's speed from a change in the returned frequency?
Doppler shift
Doppler shift, the effect that makes a passing vehicle's sound drop in pitch, also alters a radar echo's frequency; weather radars use it to track the motion of raindrops, and so the wind.
Q 25Which driver-assistance feature usually relies on a forward-facing radar?
Adaptive cruise control
Adaptive cruise control slows the car when traffic ahead slows and speeds up again when the road clears; the first systems, sold in Japan in the 1990s, used lasers instead of radar.
Q 26Which body did the US Army's Project Diana bounce radar signals off in January 1946?
The Moon
The Moon gave the project its name, after Rome's moon goddess; each echo came back about two and a half seconds after its pulse left New Jersey, the birth of radar astronomy.
Q 27Which lab made the first unambiguous radar contact with Venus, in 1961?
Jet Propulsion Laboratory
The Jet Propulsion Laboratory's echoes from Venus gave a new, far more precise value for the astronomical unit, just what was needed to steer spacecraft to other planets.
Q 28Which giant dish, used to bounce radar off planets and asteroids, collapsed in 2020?
Arecibo
Arecibo's 305 m dish was wrecked when its support cables failed and the instrument platform slung above it crashed down, shortly after officials had ruled it too unsafe to repair.
Q 29Whose 1962 Soviet paper on edge waves shaped the design of American stealth aircraft?
Pyotr Ufimtsev
Pyotr Ufimtsev's equations were translated by the US Air Force in 1971; Lockheed's Denys Overholser then built them into a program that predicted how flat panels scatter radar.
Q 30Which stealth aircraft flew in secret for years before the US Air Force first acknowledged it in November 1988?
Lockheed F-117
The Lockheed F-117 had been operational at a remote Nevada base since 1983; to keep the secret it flew only at night and spent its days shut inside hangars.