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A circular disk has a surface charge density 8nC/cm2. What will the surface charge density be if the radius of the disk is doubled?

Short Answer

Expert verified

The surface charge density if the radius of the disk is doubled from 8nC/cm2is2×104nC/m2.

Step by step solution

01

Given information 

ChargeQ=QInitialradiusr1=rChargeQi=QInitialsurfacechargedensityηi=8nC/cm2

02

Explanation

Surface charge densityη=chargearea

ni=Qr28×104ηf=Qπ4r2nf8×104=Qπ4r2Qπr2ηf=8×1044ηf=2×104nC/m2

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