Question

A positively charged rod is brought near to a neutral spherical conductor. After that, the sphere is grounded. The final charge on the sphere, after disconnecting earthing wire will be

• A. Positive
• B. Negative
• C. Zero
• D. Can't be said

Answer 1

The correct option is B Negative

When a positively charged rod is brought near a neutral sphere, it will cause redistribution of charges in the sphere due to charging by induction, as shown below.

After grounding the sphere, excess electrons will be transferred to the sphere from earth. This happens due to attraction of $e^{-}$ towards positively charged face of the sphere.

$\Rightarrow$ After the removal of connecting wire, and on taking rod back still the excess electrons remain on sphere and so sphere get negatively charged.
Hence, option $\left(B\right)$ is the correct answer.

$\begin{array}{c}\text{Why this question ?}\\ \text{Tip: After disconnecting the ground wire/earthing,}\\ \text{the excess}{e}^{-}\text{will remain on sphere.}\\ \text{Thus whether rod is removed or not, the final}\\ \text{total charge on sphere will be negative.}\end{array}$