Question

How long does it take light to reach us from the Sun, 1.53x108 km away? Give your answer in minutes.

Answer 1

Sun light takes 8.5 minutes to reach Earth.

Step-by-step explanation:

Light travels in vacuum at constant speed
`c= 3 * 10 ^8 \cfrac ms`, so we can find the time it takes to travel the given distance from Earth to Sun using a kinematic equation.

Finding the time it takes for Sun light to reach us.

Using the kinematic equation
`d = vt`, we can solve for time t, which will give us

`t = \cfrac dv`

We can replace the equation with the given values, but before doing that, we need the values to be on SI units, thus the distance becomes

`d= 1.53 * 10^8 km * \cfrac{1000 m}{1 km }\\d = 1.53 * 10^(11) m`

Replacing the values on the time equation give us

`t = \cfrac{1.53 * 10^(11) m}{3 * 10^(8) \cfrac ms}\\t = 510 s`

We get as result 510 seconds, then we must convert them in minutes.

`t = 510 s * \cfrac{1 min}{60s}\\\boxed{t = 8.5 min }`

So we can conclude that Sun light takes 8.5 minutes to reach Earth.