Question on the speed of light.

[MoreZitiPlease]

Homework Statement

An observer sees a lightning flash from a distant thunderstorm and 12 seconds later hears the second. If the temperature of the air is 20 degress celsius, how far from the storm is the observer? (assume that light travels instantaneously.

Homework Equations

None I know of.

The Attempt at a Solution

No clue. I've missed 4 days of school last week due to some sort of rash that was said to be contagious. I am very exhausted and I have no clue what I have to do. Can someone please do the problem and guide me by explaining how they solved it?

Thanks.

 

[MoreZitiPlease]

did some math and got 4083 meters.

 

[Astronuc]

One knows that speed of sound (in air) depends on the air temperature. Distance is just average speed * time

See this - http://hyperphysics.phy-astr.gsu.edu/hbase/sound/souspe.html

http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html is a good resource

 

[MoreZitiPlease]

so it is 4,123?