How long does it take (in minutes) for light to reach Venus from the Sun, a distance of 1.184 × 108 km?

Question

How long does it take (in minutes) for light to reach Venus from the Sun, a distance of 1.184 × 108 km?

 

Light travels at 2.998 × 108 m/s through space. Using this value, determine how long it will take light to travel 1.184 × 108 km. Watch your units, the distance is given in kilometers and you are asked to find the time in minutes.

 

 

 

I know the two needs to be multiplied to find the answer, but I can't figure out how to correctly convert the units since they're all different.

 

Thanks for any help. :)

Answer 1

I am sorry to say that Svetlana's answer is incorrect.

 

Light travels at 3 x 10⁸m/s which equals 3 x 10⁵km/s

 

Venus is about 1.184 × 10⁸km from the Sun

 

So. 1.184 x 10⁸km ÷ 3 x 10⁵km/s = 395seconds, or about 6.6 minutes

 

 

 

 

Answer 2

What you are given:

 

1. Distance, D,  from Venus to the sun is 1.84x10⁸km

 

2. speed of light, c,  is 2.99x10⁸m/s

 

Since the speed of light is given in m/s, the distance must first to converted from km to m.

 

1 km = 1000m

 

so 1.84x10⁸km = 1.84x10⁸km x 1000m/1km = 1.84 x 10⁸ x 10³ m = 1.84x10¹¹m 

 

The time it takes for the light to reach venus = distance / speed = D/c = 1.84x10¹¹ m / (2.99x10⁸ m/s) 

         = 1.84x10^11/2.99x10⁸ x = 615.38s

 

   But you want the answer in minutes, not seconds, so one more conversion must be done:

 

1 minute = 60s

so 615.38s = 615.38s x (1 minute / 60s) = 615.38 / 60 minutes = 10.26 minutes = time in minutes that it takes the light from the sun to arrive at Venus.