Physics - Electrostatics Question with Solution | TestHub

PhysicsElectrostaticsElectric Field & ForceHard2 minPYQ_2019

PhysicsHardsingle choice

For a uniformly charged ring of radius $R,$ the electric field on its axis has the largest magnitude at a distance $h$ from its centre. Then value of $h$ is:

Options:

Answer:

Solution:

Electric field at a distance $h$ from centre on axis

$E = \frac{1}{4 π ε_{0}} \frac{Q h}{{(R^{2} + h^{2})}^{\frac{3}{2}}}$

To get maximum $E, \frac{d E}{d h} = 0$

$0 = \frac{1}{4 π ε_{0}} \frac{Q {(R^{2} + h^{2})}^{\frac{3}{2}} - Q h \frac{3}{2} {(R^{2} + h^{2})}^{\frac{1}{2}} 2 h}{{(R^{2} + h^{2})}^{3}}$

$\Rightarrow h = \pm \frac{R}{\sqrt{2}}$

Stream:JEESubject:PhysicsTopic:ElectrostaticsSubtopic:Electric Field & Force

⏱ 2mℹ️ Source: PYQ_2019

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