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MHT CET 2024 (2 May, Shift 1) · Electric Potential & Equipotentials

Electric Potential & Equipotentials question from MHT CET 2024 (2 May, Shift 1)

Q54MHT CET 2024 · 2 MAY · SHIFT 1Difficult

Electric Potential & Equipotentials

The electrostatic potential inside a charged spherical ball is given by V=ar2+bV = ar^2 + b where ' r ' is the distance from its centre and ' aa ' and ' bb ' are constants. The volume charge density of the ball is [ ε0=\varepsilon_0 = permittivity of free space ]]

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Answer: (d)

  1. E=−dVdr=−2arE = -\dfrac{dV}{dr} = -2ar (radially).
  2. Gauss's law inside a uniform ball: E=ρr3ε0E = \dfrac{\rho r}{3\varepsilon_0}.
  3. ρr3ε0=−2ar⇒ρ=−6aε0\dfrac{\rho r}{3\varepsilon_0} = -2ar \Rightarrow \rho = -6a\varepsilon_0
  4. So the answer is (d) −6aε0-6a\varepsilon_0.
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