An air conditioner uses a compressor to raise the temperature and pressure of

An air conditioner uses a compressor to raise the temperature and pressure of refrigerant.

A refrigerant is a substance or mixture, usually a fluid, used in a heat pump and refrigeration cycle. In almost all cycles, it undertakes transformation of phases from a liquid to a gas and vice versa.

d

explanation:

v=uf/(u-f)

= 5.10/(5-10) convex lens has positive focal length

=50/-5

=-10 cm (formed at other side)

causes

fossil fuels burn

cities become more industrialized

human population grows worldwide