COMEDK · Physics · 17. Electrostatics
A pith ball of mass 'm' gram and charge 'Q' is suspended using a mass less silk thread near a large charged conducting metal sheet of area 'A' and surface charged density '\(\sigma\)'. If the silk thread makes an angle \(\Theta\) with the metal sheet, then:
- A \(\tan\theta \propto mg\)
- B \(\tan\theta \propto A\)
- C \(\tan\theta \propto \dfrac{1}{\sigma}\)
- D \(\tan\theta \propto \sigma\)
Answer & Solution
Correct Answer
(D) \(\tan\theta \propto \sigma\)
Step-by-step Solution
Detailed explanation
The electric field near a large charged conducting metal sheet is given by \(E = \dfrac{\sigma}{\epsilon_0}\). The electric force acting on the pith ball is \(F_e = QE = \dfrac{Q\sigma}{\epsilon_0}\). The gravitational force acting downwards on the pith ball is \(W = mg\). Let…
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