First calculate the <em>percentage of one hr</em> it takes. You can do this by dividing the distance by the velocity. The general formula for this is:

always remember to make sure your units are the same.
so that's 1km by the 950km/h velocity.
1/950 = 0.0010526 hrs
Then multiply that answer by 3600 (<em>the number of seconds in 1 hr</em>) to find how many seconds this is.
0.0010526 * 3600 = 3.789 seconds
Answer:
Wavelength of electromagnetic wave will be 5.281 m
Explanation:
We have given frequency of electromagnetic wave is 
Velocity of electromagnetic wave is 
We have to fond the wavelength of the electromagnetic wave
We know that velocity of electromagnetic eave is given by
, here
is wavelength and f is frequency
So 
Wavelength of electromagnetic wave will be 5.281 m
Yes because there is more echo and a larger volume for the sound waves to travel