An electrostatic paint sprayer has a metal sphere of diameter $18 \mathrm{~cm}$ and at a potential of $25…

An electrostatic paint sprayer has a metal sphere of diameter $18 \mathrm{~cm}$ and at a potential of $25 \mathrm{kV}$. The charge on the metal sphere is
  1. $0.25 \mu \mathrm{C}$
  2. $2.5 \mu \mathrm{C}$
  3. $0.5 \mu \mathrm{C}$
  4. $25 \mu \mathrm{C}$

Solution

As, $V=\frac{k q}{r}$ So, $q=\frac{V \times r}{k}=\frac{25 \times 10^3 \times 9 \times 10^{-2}}{9 \times 10^9}$ $=25 \times 10^{-8} \mathrm{C}=0.25 \mu \mathrm{C}$

Asked in: AP EAMCET 2017 (26 Apr Shift 1)

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