Physics - Electrostatics Question with Solution | TestHub

PhysicsElectrostaticsElectric Field & ForceMedium2 minPYQ_2020
PhysicsMediumsingle choice

A wire of lengthL=20 cmis bent into a semi-circular arc and the two equal halves of the arc are uniformly charged with charges+Qand-Qas shown in the figure. The magnitude of the charge on each half isQ=103ε0, whereε0is the permittivity of free the space. The net electric field at the centreOis

Options:

Answer:
A
Solution:



L=πR

⇒R= L π = 20 100π   m= 1 5π   m

⇒due to a charge arc, electric field at centre is given by

E= 2Kλ R sin θ 2



E1=E2=2k⋋Rsin⁡902         {⋋=QπR/2}


E 1 =E 2 = 2 2  KQ π R 2

Component alongj^ gets cancelled and

E net = 2 E 1

= 4KQ π R 2

=4×1103ϵ04πϵ0 πR2=4×103ϵ04π2ϵ0R2=102R2=10015π2=25×103

E→net=25×103NC i^

Stream:JEESubject:PhysicsTopic:ElectrostaticsSubtopic:Electric Field & Force
⏱ 2mℹ️ Source: PYQ_2020

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