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Crystal radio: Quiz


Question 1: As electronics evolved, the ability to send voice signals by radio caused a technological explosion in the years around 1920 that evolved into today's radio ________ industry.
BroadcastingTelevision stationBroadcast engineeringMass media

Question 2: A ________ to select the signal of the radio station to be received, out of all the signals received by the antenna.
RLC circuitRC circuitLC circuitRL circuit

Question 3: Crystal radios are the simplest type of radio receiver,[1] and can be handmade with a few inexpensive parts, like an antenna wire, tuning coil of copper wire, ________ and earphones.
DiodeSiliconCat's-whisker detectorLead

Question 4: [11] At the end of that era, around 1920, they were superseded by the first amplifying receivers, which used vacuum tubes (________), and became obsolete for commercial use.
Audion tubeJohn Ambrose FlemingLee De ForestCoherer

Question 5: This was used in the telephone industry and in ________ nearly since the invention of both components and long before vacuum tubes.
Sensorineural hearing lossHearing impairmentHearing aidAudiology

Question 6: The low power produced by crystal radios is insufficient to power a ________ so earphones are used.
Loudspeaker enclosureSubwooferTweeterLoudspeaker

Question 7: Crystal radios can be designed to receive almost any radio frequency band, but most receive the ________ band.
AM stereoAM broadcastingShortwaveMedium wave

Question 8: The first crystal sets received wireless telegraphy signals broadcast by ________ at frequencies as low as 25 kHz.
Nikola TeslaSpark gapRadioSpark-gap transmitter

Question 9: A needle-sized air pipe was placed near a sound membrane, which acted as an air ________ and modulated the air flow, amplifying the sound.
Diesel engineEngineInternal combustion engineValve

Question 10: An ________ to convert the audio signal to sound waves so they can be heard.
Headset (telephone/computer)HeadphonesSound recording and reproductionLoudspeaker


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