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$$\sigma$$ is the uniform surface charge density of a thin spherical shell of radius $$R$$. The electric field at any point on the surface of the spherical shell is :
We need to find the electric field at any point on the surface of a thin spherical shell with uniform surface charge density $$\sigma$$ and radius $$R$$.
The total charge on the shell is $$Q = \sigma \cdot 4\pi R^2$$.
By Gauss's law, the electric field just outside the shell (at distance $$R$$ from center) is:
$$E_{\text{outside}} = \frac{Q}{4\pi\epsilon_0 R^2} = \frac{\sigma \cdot 4\pi R^2}{4\pi\epsilon_0 R^2} = \frac{\sigma}{\epsilon_0}$$
The electric field just inside the shell is $$E_{\text{inside}} = 0$$ (no enclosed charge for a Gaussian surface inside).
For a conducting shell or a charged surface, the electric field AT the surface is taken as the value just outside the surface, which is $$\frac{\sigma}{\epsilon_0}$$. This is the standard convention used in JEE for the field "on the surface" of a spherical shell.
The correct answer is Option B: $$\sigma/\epsilon_0$$.
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