Question

A space probe on the surface of mars sends a radio signal back to earth,a distance of 7.19 ×10⁷ km. Radio travel at the speed of light (3.00 ×10⁸ m/s). How many seconds does it take for the signal to reach the earth?

Answer 1

The time taken by the signal to reach the earth is 240 s.

Step-by-step explanation:

As it is known that speed of any particle is defined as the rate of change in distance per unit time. So depending upon how much distance is covered in a given time, the speed of that travelling particle can be determined. In this case, the distance to be covered is given as
`7.19*10^(7)` km . And it is also known that any radio signal travels with the speed of light. So the speed or velocity of the signal is given as
`3*10^(8)` m/s. Thus,
`Speed = (Distance)/(Time)`. So,
`Time =(Distance)/(Speed)`. Since the distance is given in km, we have to convert it to meter.

Thus,
`Time = (7.19*10^(7)*10^(3)  )/(3*10^(8) )`.

So,
`Time = 2.397*10^(7+3-8)=2.397*10^(2)=240 s`.

Thus, nearly 240 s are required by the signal to reach the earth.