Infrared radiations are produced when a changing electric field creates a

longitudinal wave parallel to it
longitudinal wave perpendicular to it
changing magnetic field parallel to it
changing magnetic field perpendicular to it

Option (d)

Explanation:

When an oscillating electric and magnetic fields interacts each other perpendicularly then electromagnetic radiations are produced.

Here the changing magnetic field is created perpendicular to electric field

increases it

answer: the metamorphic rocks are formed when they are exposed to high pressure and high temperatures. this happens when one of the earth's plates comes in contact with the other plate by traveling in opposite directions, straight into each other or slipping under one another. the friction that is caused by this activity results in   melting of rocks and when it cools they are known as metamorphic rocks. this process needs a controlled amount of pressure and temperature otherwise it may turn into magma.