Question

which of the following is used as the photosensitive substance in Xerox machine
A) Hg
B)Black p
C) Se
D) Te

Answer 1

negatively charged yellowish moss spores (lycopodium) on a sulfur-coated zinc plate 



also for different colours ,different metals where used

Answer 2

Correct option is C. Selenium

Selenium is a element which is non metallic chemical used in the process of  photocopying.

In these process of photocopying, the round drum is present which is of aluminum and inside the copier a layer of selenium is coated which is give positive electrical charge. When the document is place on the top of the glass surface, a light is fall on the document that to be copy and onto the drum which cause positive charged. The negatively charged toner is then spray over the drum and thus form an exact copy of the original  document.