# Question 4555c

##### 1 Answer
Nov 5, 2016

It will take 200 s for the radio signal to reach Mars.

#### Explanation:

The speed of light, $c$ is $3.00 \times {10}^{8}$ $\text{m/s}$ to three significant figures. All electromagnetic radiation, such as radio waves, travel at the speed of light. Since $c$ is in m/s, convert the distance to Mars from kilometers to meters by multiplying kilometers by 1000.

$60 , 000 , 000 \cancel{\text{km"xx(1000"m")/(1cancel"km")=60,000,000,000 "m"=6.00xx10^10"m}}$

Now divide the distance in meters by the speed of light in m/s.

(6.00xx10^10cancel"m")/(3.00xx10^8cancel"m"/"s")="200 s"#