Q.

An infinitely long thin wire, having a uniform charge density per unit length of 5 nC/m, is passing through a spherical shell of radius 1 m, as shown in the figure. A 10 nC charge is distributed uniformly over the spherical shell. If the configuration of the charges remains static, the magnitude of the potential difference between points P and R, in Volt, is ________.

[Given: In SI units 14πε0=9×109, ln 2=0.7. Ignore the area pierced by the wire.]                       [2024]


Ans.

(171)

Due to wire,  dV=-E.dx

VPVRdV=-0.522kλxdx

VR-VP=-2kλln(20.5)

=-2×9×109×3×10-9×2×0.7=-126 V

Due to sphere,

VR-VP=kQ2-kQ1=-kQ2

=-9×109×10×10-92=-45 V

VR-VP=-126-45=-171 V

or,    VP-VR=171 V