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CUET · MATHS · PYQ PAPER 2024

A copper ball of density \(8 ~ g / c c\) and \(1 c m\) diameter, immersed in oil of density 0.8 \(g / cc\), remains suspended in an electric field of \(600 \pi V / m\). The charge on the ball is :

  1. A \(2 \times 10^6 C\)
  2. B \(2 \times 10^{-5} C\)
  3. C \(1 \times 10^{-5} C\)
  4. D \(1 \times 10^{-6} C\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(2 \times 10^{-5} C\)

Step-by-step Solution

Detailed explanation

\(F_e + F_b = F_g\) \(q E = (\rho_b - \rho_{oil}) \frac{4}{3} \pi r^3 g\) \(q = \frac{(8 \times 10^3 - 0.8 \times 10^3)~kg/m^3 \times \frac{4}{3} \pi (0.5 \times 10^{-2}~m)^3 \times 10~m/s^2}{600 \pi~V/m}\)…