Question

How many nanoseconds does it take light to travel a distance of 3.80 km in vacuum? Express your answer numerically in nanoseconds.

Answer 1

1.27 × 10⁴ ns

Step-by-step explanation:

Given data

• Distance (d): 3.80 km = 3.80 × 10³ m

• Speed of light (v): 3.00 × 10⁸ m/s

We can find the time (t) that it takes to the light to travel 3.80 km using the following expression.

v = d/t

t = d/v

t = (3.80 × 10³ m)/(3.00 × 10⁸ m/s)

t = 1.27 × 10⁻⁵ s

We know that 1 s = 10⁹ ns. Then,

1.27 × 10⁻⁵ s × (10⁹ ns/1s) = 1.27 × 10⁴ ns

Answer 2

t=12600ns

Step-by-step explanation:

We use the relation between distance and velocity to solve this problem:

d=v*t

d=3.8km=3.8*10^3m

v=3*10^8 m/s^2 light's speed

we solve to find t:

t=d/v=(3.8*10^3)/(3*10^8)=1.26*10^(-5)s=12600*10^(-9)s=12600ns