Electrostatics question. just need a bit direction.

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Homework Help Overview

The discussion revolves around an electrostatics problem related to the expansion of the Universe, specifically involving the charge of hydrogen atoms and the balance between electric repulsion and gravitational attraction.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to analyze the implications of a net charge on protons and its effect on the expansion of the Universe, starting with a Gaussian surface approach. Some participants question the nature of forces involved, specifically whether they refer to interactions within atoms or between atoms.

Discussion Status

Participants are exploring the relationship between electric and gravitational forces in the context of the problem. There is a focus on clarifying the types of forces being discussed, but no consensus has been reached regarding the implications of the charge on the protons.

Contextual Notes

The problem involves assumptions about the charge of protons and the conditions necessary for the expansion of the Universe, which may not be fully defined in the discussion.

PrashntS
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I was trying to solve this one, but couldn't come up with any way to start.

In 1959 Lyttleton and Bondi suggested that the expansion of the Universe could be explained if matter carried a net charge. Suppose that the Universe is made up of hydrogen atoms with a number density N, which is maintained a constant. Let the charge on the proton be: ep = – (1 + y)e where e is the electronic charge.
(a)Find the critical value of y such that expansion may start.
(b)Show that the velocity of expansion is proportional to the distance from the centre.

Attempt at solution-

since charge assumed on proton is -(1+y)e, there is net charge in atom. also the force is repulsive, not attractvie. I started with taking a spherical gaussian surface and thts it! i couldn't go any further.
 
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Gravity between the hydrogen atoms is an attractive force. The extra charge has to be so great that electric repulsion overcome gravitational attraction.

ehild
 
ehild said:
Gravity between the hydrogen atoms is an attractive force. The extra charge has to be so great that electric repulsion overcome gravitational attraction.

ehild

by this, do you refer to force inside the atom, between electron and proton, or between atoms.

and thanks fir quick reply. :-)
 
PrashntS said:
by this, do you refer to force inside the atom, between electron and proton, or between atoms.

and thanks fir quick reply. :-)

Between the atoms.

ehild
 

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