Question

A certain radar installation tracks airplanes by transmitting electromagnetic radiation of wavelength 4.0 cm.

a)Find the frequency of this radiation. b)Find the time required for a pulse of radar waves to reach an airplane 4.8 km away and return.

Answer 1

the wavelength equation is

speed (of light in this case)= wavelength (m) x frequency

3x10^8m/s / .07m = f

frequency= 4 285 714 286 hertz

b) Total distance= 4.8 km (4,800 m)

Speed = 3x10^8 m/s

d=st

t= d/s

t= 4,800 m/3x10^8m/s

t= 1x10^-5 seconds

Answer 2

a) frequency =
`7.5 * 10^9 hz`

b) times =
`3.2 * 10^(-5) s`

Step-by-step explanation:

Part a)

As we know that frequency of radiation is given as

`frequency = (speed)/(wavelength)`

now we know that

`speed = 3 * 10^8 m/s`

`wavelength = 4 cm`

now frequency is given as

`f = (3 * 10^8)/(4 * 10^(-2))`

`f = 7.5 * 10^9 Hz`

Part b)

Time required for the pulse to reach the airplane and return is given by formula

`t = (distance)/(speed)`

total distance for moving to and fro = 4.8 km + 4.8 km = 9.6 km

speed of the wave =
`3 * 10^8 m/s`

now times is given as

`t = (9.6 * 10^3)/(3 * 10^8)`

`t = 3.2 * 10^(-5) s`