The correct option is B 27
Given that,
Radius of the sphere, R=0.5 m
Charge of the sphere, Q=10×10−10 C
The given integral represent the relation between electric field and electric potential.
−0∫∞→E⋅→dr = Potential at centre of sphere - Potential at infinity
The potential at infinity is zero
⇒V∞ = 0
The potential at the centre of the sphere is
Vcentre=3kQ2R
Vcentre=3×9×109×10×10−102×0.5=27
So −0∫∞→E⋅→dr=27