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AP EAMCET · PHYSICS · Electrostatics

If four charges \(+12 \mathrm{nC},-20 \mathrm{nC},+32 \mathrm{nC}\) and -15 nC are arranged at the four vertices of a square of side \(\sqrt{2} \mathrm{~m}\), then the net electric potential at the centre of the square due to these four charges is

  1. A 72 V
  2. B 81 V
  3. C 64 V
  4. D 36 V
Verified Solution

Answer & Solution

Correct Answer

(B) 81 V

Step-by-step Solution

Detailed explanation

\(r = \frac{\sqrt{2} \cdot s}{2}\) \(r = \frac{\sqrt{2} \cdot \sqrt{2}}{2} = 1 \, \mathrm{m}\) \(V_{net} = \frac{k}{r} \sum q_i\) \(V_{net} = \frac{9 \times 10^9}{1} (12 - 20 + 32 - 15) \times 10^{-9}\) \(V_{net} = 9 \times 9 = 81 \, \mathrm{V}\)