Name: David P. Bligh
What is the radius of a proton?
The radius of a proton depends on how you mean radius. It turns out that a
proton is not actually a ball. Latest experiments show that a proton is
made of three smaller particles called quarks. Quarks have a size too small
to measure. They may have no size at all. These three quarks spin around
each other very quickly. In reality, a proton does not have a radius. As
for radius of orbits, that involves an area of quantum mechanics that is
still being explored. We do not yet know enough about the force between
quarks to determine a value for orbit sizes within a proton, or a neutron.
Dr. Ken Mellendorf
Illinois Central College
Atomic nuclei are roughly spherical, and have a radius given by:
Ro = 1.2x10^-15 meters and A is the atomic number. These are experimentally
determined by electron scattering.
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Update: June 2012