A glass rod, rubbed with silk gets positively charged, why?

The correct answer is Option (3) → due to deficiency of electrons

In charging by friction only electrons move from one body to the other; the protons stay fixed inside the nuclei. A body that loses electrons has more protons than electrons and is positively charged.

Glass holds its outer electrons less firmly than silk, so electrons pass from the glass rod to the silk. The rod is left with a deficiency of electrons, and the silk, with the same number of extra electrons, becomes negatively charged.

Positrons are not involved in rubbing, and protons cannot be removed from a nucleus by friction, so the other options do not describe the process.

NCERT (2026-27):
Electric Charge – “… When we rub a glass rod with silk, some of the electrons from the rod are transferred to the silk cloth. Thus the rod gets positively charged and the silk gets negatively charged.”