Re: [Phys-l] Prising electrons from the atom

[John Denker <jsd@av8n.com>]

On 12/17/2008 08:05 AM, sridhar chitta wrote:

> 1)      What kind of force keeps the electrons away from the nucleus.

I'm not sure we have a name for this force that has dimensions
of force.  However:
 -- If you quantify it as force per unit area it is properly 
  called "the pressure".
 -- If you quantify it in units of energy it is called "the 
  kinetic energy".

>       Can this be called a "nuclear" force ? 

Absolutely not.

> I have been teaching students
> that there are four fundamental forces in nature and that all other forces
> are derived from these. 

The "forces" (i.e. interactions) on that list are all contributions 
to the _potential_ energy.  Kinetic energy is a horse of a different 
color.

KE is undoubtedly fundamental, but it does not usually appear on the
list of fundamental interactions ... perhaps because it is not an
interaction.


>       "The *nuclear forces* between these two types of objects is so strong
> that no earthly conditions can cause the electrons to merge with the
> nucleus, even though they are opposite in charge".

Radioactivity is an "earthly" occurrence.  Electron capture (i.e.
inverse beta-decay of a neutron) is readily observable.  It is 
the merger of an electron into a nucleus.


> 2)      Why cannot a hammer and chisel that can exert a force of say, 100
> Newtons be used to prise an electron away from the nucleus of a copper atom

How do you know it can't be done?
How sure are you?

Hint:  triboelectricity (aka "static electricity").  There's lots
of that this time of year (in northern temperate regions).