Question
One end of a 10cm long silk thread is fixed to a large vertical surface of a charged nonconducting plate having a mass 10g and a charge of 4*10^-6 c . In equlibrium the thread makes an angle of 60 deg. With he vertical.find the surface charge density on plate.Joshi sir comment
according to the diagram
tanθ = qE/mg = q(σ/2ε0)/mg
solve this eq. for σ.
Remember that length of the thread is not applicable in the question.
Read 1 Solution.
ANS 7.514*10-7 C/m2
According to the given data in the problem
tanθ= qe/mg
=q(δ/2ε0)/mg
after substituting the values we get the answer as give above.
BRAHMAIAH 11 year ago
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