**Question. The surface densities on the surfaces of two charged spherical conductors of radii R _{1} and R_{2} are equal. The ratio of electric intensities on their surfaces is:**

a) R_{1}^{2} / R_{2}^{2}

b) R_{2}^{2} / R_{1}^{2}

c) R_{1} / R_{2}

d) 1 : 1

**Answer: d) 1 : 1**

Let the surface densities on the surfaces of two charged spherical conductors of radii R1 and R2 be σ1 and σ2 respectively.

But σ1=σ2 …(given)Electric field intensity on surface of spherical conductor is given by,

E=Q/4πϵ_{o}r^{2}=σ/ϵ_{o}

∴ Ratio of electric field intensities on their surfacesis given by,

E1/E2 = σ_{1}/ϵ_{o}/ σ_{2}/ϵ_{o} =σ1 / σ_{2} = 1/1 …(σ1=σ2)

∴E1:E2=1:1