help with basic EE question

[kickureface]

having some trouble with this one-
signal travels via optical fiber from LA to chicago 3000km away. the signal is 10^6 bytes at 10^8 bits/sec
a. how long is the signal in seconds.
b. if the first signal bit leaves LA at t=0, when does it reach chicago?
c. when does the last signal reach chicago

part a is simple, some division and unit conversion
part b and c throw me off-am i suposed to know how fast signal bits are? and how much separation is between the first and last bits?

 

[Phyzzle]

I hope you're in High School and not College, heh.

am i suposed to know how fast signal bits are?

Well, the signal bits are light . . . so how fast is light? Are you given the refractive index of fiber-optic glass anywhere?

 

[Mr. Wolf]

a. (10^6 * 8) / 10^8 = (10^14) / 10^8 = 10^6 = sL - signal length in seconds.

b. t_chicago = 1/(3000km / c) + t + k

where c is speed of light in km per seconds.. k is some sort of constant that slows light down as it travels.

c. t_chicago seconds + sL