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2. Electric potential and capacitance — Physics STD 12 Science — Question

CBSE BoardEnglish MediumSTD 12 SciencePhysics2. Electric potential and capacitance1 Mark
MCQ
Consider a sphere of radius $R$ having charge $q$ uniformly distributed inside it. At what minimum distance from its surface the electric potential is half of the electric potential at its centre?
  • A
    $R$
  • B
    $\frac{R}{2}$
  • C
    $\frac{4 R}{3}$
  • ✓
    $\frac{R}{3}$
✓

Answer

Correct option: D.
$\frac{R}{3}$
d
(d)

$V_c=\frac{3 k Q}{2 R}$

$V_s=\frac{k Q}{R+x}=\frac{3 k Q}{4 R}$

$4 R=3 R+3 x$

$3 x=R$

$x=\frac{R}{3}$

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