What two things must exist for an electric current to be produced?A pair of highly conductive materials and a conducting path be
tween themA source of voltage and an open circuitA negatively charged electrode and a positively charged electrodeAn electric potential between two bodies and a conducting path joining the bodies
The two things that must exist for an electric current to be produced are:
An electric potential between two bodies and a conducting path joining the bodies.
This comes from the fact that when there is a potential difference there is an electrical field and hence a force that makes some free charges to move in the conductor. For this reason, there's an electrical current.
We have many uses for infrared: night-vision cameras, remote controls, infrared astronomy, and fiber-optic cables. The greenhouse effect is even related to infrared waves because greenhouse gases absorb the infrared emitted by the ground, trapping it on the Earth.