Verified Solution • 2025–26 Session moderate

QJEEM18Phf317: JEE Main 2018 Physics - Class 12 JEEM18Phf317 Solution: Two identical conducting spheres A and B, carry equal charge.…

Two identical conducting spheres A and B, carry equal charge. They are separated by a distance much larger than their diameters, and the force between theis F. A third identical conducting sphere, C, is uncharged. Sphere C is first touhed to A, then to B, and then removed. As a result, the force between A and B would be equal to :

Multiple Choice Options

  • A F
  • B 3F4
  • C 3F8
  • D F2

Step-by-Step Verified Solution

Let, change of A and B = q

∴ Force between them, F = k×q×qr2=kq2r2

When C touched with A then charge of A. Will fl;ow to C and divide into half parts.

∴ charge of A and C ,

qA = qB = q2

Then C touched with B, then charge on B,

qB = q2+q2=3q4

∴ Force between A and B,

F' = k×q2×3q4r2

= k×3q28r2

= 38×kq2r2

= 38F

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