Question

Crystals have 'vacant sites' or 'defects' in them. When light strikes a photographic silver bromide paper, silver atoms move in through these defects to:

• A. develop the film
• B. form tiny clumps of silver atoms
• C. form negative images
• D. form a colour image

Answer 1

The correct option is C form negative images

When light strikes a photographer $\left(AgBr\right)$ paper, it gives energy to the electrons present in the film. These energetic electrons when strike silver ions turn them to silver atoms. So eventually, ions leave their lattice site and occupy interstitial sites. Since silver atoms are black in color so whenever light strikes a silver ion the photographic film will turn black.