Verified Solution • 2025–26 Session moderate

QJEEM24Phc1f2: JEE Main 2024 Physics - Class 12 JEEM24Phc1f2 Solution: Two charged conducting spheres of radii and are connected to…

Two charged conducting spheres of radii aa and bb are connected to each other by a conducting wire. The ratio of charges of the two spheres respectively is:

Multiple Choice Options

  • A aba b
  • B ba\frac{b}{a}
  • C ab\frac{a}{b}
  • D ab\sqrt{a b}

Step-by-Step Verified Solution

When two conducting spheres of radii aa and bb are connected by a conducting wire, they come to the same potential because conductors in contact share charges until their potentials become equal. The potential of a charged sphere is given by V=kQRV = \frac{kQ}{R} , where VV is the potential, kk is Coulomb's constant, QQ is the charge on the sphere, and RR is the radius of the sphere.

For the two spheres at the same potential, we have:

kQaa=kQbb\frac{kQ_a}{a} = \frac{kQ_b}{b}

Where:

  • QaQ_a and QbQ_b are the charges on the spheres with radii aa and bb , respectively.
  • kk cancels out from both sides as it is a constant.

From the above equation, to find the ratio of charges QaQb\frac{Q_a}{Q_b} , we rearrange it as follows:

QaQb=ab\frac{Q_a}{Q_b} = \frac{a}{b}

Therefore, the ratio of the charges of the two spheres respectively is ab\frac{a}{b} .

So, the correct answer is Option C: ab\frac{a}{b} .

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