# Electrostatics question. just need a bit direction.

1. Oct 22, 2012

### PrashntS

I was trying to solve this one, but couldnt 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 couldnt go any further.

2. Oct 22, 2012

### ehild

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

ehild

3. Oct 22, 2012

### PrashntS

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

and thanks fir quick reply. :-)

4. Oct 22, 2012

### ehild

Between the atoms.

ehild