Question

The distance from the Old North Church in Boston to Charlestown is approximately 1,410 meters . Even on fast horse , that distance would take several minutes to travel . On April 18 , 1775 , lanterns were shown from the steeple of the Old North Church across the Charles River to warn American patriots that British soldiers were travelling Inland via water . The speed of light is approximately 3 x 10 to the power of 8 meters per second . How many seconds did it take for the light to be visible in Charlestown ?

Answer 1

We were told that the distance from the Old North Church in Boston to Charlestown is approximately 1,410 meters.

Given that the speed of light is approximately 3 x 10 to the power of 8 meters per second and

speed = distance/time

It means that the number of seconds it took for the light to be visible in Charlestown is also the time it took the light to travel through 1410 meters

Therefore,

time = distance/speed

time = 1410/3 * 10 ^8 = 0.0000047 seconds

time = 4.7 * 10^-6 seconds