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Surface area of the earth

  • #1

Homework Statement


Near Earth, the density of protons in the solar wind (a stream of particles from the Sun) is 8.60 cm-3 and their speed is about 490 km/s.
(a) Find the current density of these protons.
6.74E-7 A/m^2
(b) If Earth's magnetic field did not deflect the protons, what total current would Earth receive?


Homework Equations


J=I/A


The Attempt at a Solution


Using the equation above i used J*A=I, the problem is the area is used for the earth is apparently wrong(as i know my J is correct), so i looked online for it again and found 2 more answers(all the same numbers but to different powers of 10). Anyone know the actual surface area of the earth?(i would try plugging on all the ones i find but im limited on attempts for this question and i already used 2/5 of my tries)
 

Answers and Replies

  • #2
ehild
Homework Helper
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All those protons will reach the Earth which are in the beam of cross-section equal to that of the Earth.

ehild
 
  • #3
Lok
555
23
What surface area do you need, the sphere or crossection?
 
  • #4
What surface area do you need, the sphere or crossection?
id assume surface, what is corssection?
 
  • #5
Lok
555
23
id assume surface, what is corssection?
There is the surface of the earth, which is somewhat a sphere or it's crossssection or the surface the electrons hit, so the area of a circle with the radius of earth. Which one have you been looking for and which one do you need?
 

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