Amateur Radio Quiz: Puzzled at Times
- What is the length of a day measured by the position of distant stars?
- What was added by the world's standard timekeepers on December 31, 2008?
a) A leap second
b) Two leap seconds
c) A new definition of the second
d) A time zone
- How many time zones are recognized?
- What is the largest country with a single time zone?
- How far does light travel in free-space during one femtosecond?
a) 1 nanometer
b) 3 nanometers
c) 300 nanometers
d) 1 micrometer
- Which country spans the most time zones?
- Which is longer: a millennium or an eon?
- How long does it a radio signal to travel all the way around the Earth?
a) 7 msec
b) 100 msec
c) 1/7th of a second
d) 7 seconds
- How long does it take an EME signal to make the trip from the Earth to the Moon and back again?
a) 1/7th of a second
b) 1 second
c) 1.35 seconds
d) 2.7 seconds
- How far does your 80 meter signal travel during the time it takes the direction of electromagnetic fields to make one complete oscillation as determined by an observer traveling with the wave?
a) 1 meter
b) 40 meters
c) 80 meters
Bonus: What astronomical phenomena were used around the world to determine standard time before reliable chronometers were available?
- b (see http://en.wikipedia.org/wiki/Sidereal_day)
- a (see http://www.timeanddate.com/time/leapseconds.html)
- d (see http://en.wikipedia.org/wiki/Time_zones)
- c -- although China could span five time zones, its official time uses a single time zone
- c -- 3 x 10^8 m/sec times 1 x 10^-15 = 3 x 10^-7 m = 300 x 10^-9 m = 300 nm
- A millennium is one thousand years and an eon is one billion years
- d – to an observer traveling with the wave (at the speed of light), the direction of the fields do not change!
Bonus: Occultations of the moons of Jupiter were observed through a telescope and compared to standard time tables prepared by observatories (http://www.topogs.org/jupiter.htm).
H. Ward Silver, N0AX