Question

A positive point charge $Q$ is brought near an isolated neutral metal cube. Then choose the correct option.

• A. The cube becomes negatively charged.
• B. The interior remains charge free and the surface of cube gets non-uniform charge distribution
• C. The interior becomes positively charged and the surface of cube becomes negatively charged
• D. The cube becomes positively charged.

Answer 1

The correct option is B The interior remains charge free and the surface of cube gets non-uniform charge distribution


By induction, the surface near the point acquires non uniform negative charge because the electric field strength due to point charge is different at different points on the front surface of metal cube.

Since the cube is conductive, all the charge should reside on the surface and the interior remains charge free.

Also, as the cube is conductive, the rear surface of the cube acquires non-uniform positive charge to balance the total charge on the cube.

Hence, most appropriate correct answer is $\left(d\right)$.