Chapter 29, Problem 35PE

### College Physics

1st Edition
Paul Peter Urone + 1 other
ISBN: 9781938168000

Chapter
Section

### College Physics

1st Edition
Paul Peter Urone + 1 other
ISBN: 9781938168000
Textbook Problem

# (a) How far away must you be from a 650-kHz radio station with power 50.0 kW for there to be only one photon per second per square meter? Assume no reflections or absorption, as if you were in deep outer space. (b) Discuss the implications for detecting intelligent life in other solar systems by detecting their radio broadcasts.

To determine

(a)

The distance far away must you be from a 650 kHz radio station with power 50.00 kW for there to be only one photon per second per square meter.

Explanation

Given info:

â€ƒâ€ƒf=650Â kHz

â€ƒâ€ƒp=50Â kW

â€ƒâ€ƒh=6.63Ã—10âˆ’34Â Js

Formula used:

For energy in photon in radio waves, the relation between energy and frequency is

â€ƒâ€ƒEâ‰ˆhf

Calculation:

Substituting the given values of frequency in relation with time, we get

â€ƒâ€ƒf=1T

Substituting the values, we get

â€ƒâ€ƒf=650Ã—103pulses/s

Now Energy of radio waves is

â€ƒâ€ƒEâ‰ˆ6.63Ã—10âˆ’34Ã—650Ã—103Â JEâ‰ˆ4.31Ã—10âˆ’28Â J

The number of photons per second are emitted by the flux of the satellite, we get

â€ƒâ€ƒp=nEÂ Â

Substituting the given values

â€ƒâ€ƒn=pEÂ Â

Substituting the given values of joule in term of electron volt, we get

â€ƒâ€ƒ1J=11.6Ã—10âˆ’19Â eV

â€ƒâ€ƒn=50.0Ã—103Â Js4

To determine

(b)

This implications for detecting intelligent life in other solar systems by detecting their radio broadcasts.

### Still sussing out bartleby?

Check out a sample textbook solution.

See a sample solution

#### The Solution to Your Study Problems

Bartleby provides explanations to thousands of textbook problems written by our experts, many with advanced degrees!

Get Started