Which of the following point defects are shown by AgBr (s) crystals?
I. Schottky defect
II. Frenkel defect
III. Metal excess defect
IV. Metal deficiency defect

AgBr shows both Schottky as well as Frenkel defect. In AgBr both Ag⁺ and Br^- ions are absent from the lattice causing Schottky defect.
However, Ag⁺ ions are mobile, so they have a tendency to move aside the lattice and trapped in interstitial site, hence cause Frenkel detect.