Electric charges and field

• An early model for an atom considered it to have a positively charged point nucleus of charge Ze,surrounded by a uniform density of negative charge up to a radius R.The atom as a whole is neutral.For this model what is the electric field at a distance r from the nucleus.pls.. expalin this answer in a different way other then the one given in the textbook.
Ans= E=0

• @sri
When r <=R, E(r) = 0
When r >R, E(r) = Ze/4π£° (1/r^2 - r/R^3)

STEPS AND Understanding :

1. We know, that size of Nucleus in negligible as compared to Nucleus.
So, At any distance r, we have to understand there exists nucleus with charge( +Ze. )

2. As atom is Neutral, the total Negative Charge in a sphere of Radius R is (-Ze. )

1. We will find Negative charge density to calculate charge at any distance r.

2. We will. apply Gauss law to find Electric Field at less than equal to R distance and more than that.

For Calculation see pic   Looks like your connection to dubbtr was lost, please wait while we try to reconnect.