Q 01/05

What does the acronym RADAR stand for?

A) Range and distance recorder

B) Radio direction and range

C) Radio detection and ranging

D) Radiated angle detection array

Answer · why

C) Radio detection and ranging

The word has since become an anacronym, a plain noun with no capitals.

Q 02/05

Which organisation coined the term RADAR in 1940?

A) The Royal Air Force

B) The US Navy

C) The German Luftwaffe

D) The BBC

Answer · why

B) The US Navy

Britain had been calling the technology RDF, for radio direction finding.

Q 03/05

Which German physicist showed in 1886 that radio waves reflect off solid objects?

A) Wilhelm Röntgen

B) Ferdinand Braun

C) Max Planck

D) Heinrich Hertz

Answer · why

D) Heinrich Hertz

He was the first to prove the existence of the electromagnetic waves Maxwell's equations predicted.

Q 04/05

Which German inventor patented the 'telemobiloscope' in 1904 to detect ships in fog?

A) Christian Hülsmeyer

B) Werner von Siemens

C) Rudolf Kühnhold

D) Karl Ferdinand Braun

Answer · why

A) Christian Hülsmeyer

It could sense a distant ship's presence but not measure its distance, and the military rejected it.

Q 05/05

Which Russian physicist noted in 1897 that a passing ship disturbed radio signals?

A) Dmitri Mendeleev

B) Alexander Popov

C) Pyotr Lebedev

D) Konstantin Tsiolkovsky

Answer · why

B) Alexander Popov

He wrote that the effect might detect objects but did nothing more with it.