Question

If the Sun suddenly went dark, we would not know it until its light stopped arriving on Earth. How long would that be, in seconds, given that the Sun is 1.50 × 1011 m away?

Answer 1

Answer: 500 s

Explanation:

Speed $v$ is defined as a relation between the distance $d$ and time $t$:

$v=\frac{d}{t}$

Where:

$v=3(10)^{8}m/s$ is the speed of light in vacuum

$d=1.5(10)^{11}m$ is the distance between the Earth and Sun

$t$ is the time it takes to the light to travel the distance $d$

Isolating $t$:

$t=\frac{d}{v}$

$t=\frac{1.5(10)^{11}m}{3(10)^{8}m/s}$

Finally:

$t=500 s$