What happened to the weather after mount tambora epurted?

The eruption of Mount Tambora eventually reduced the average global temperature by as much as 3 °C.

Explanation:

The Mount Tambora eruption was the largest and most destructive volcanic event in recorded history, expelling as much as 150 cubic km (roughly 36 cubic miles) of ash, pumice, and other rock, and aerosols—including an estimated 60 megatons of sulfur—into the atmosphere. As that material mixed with atmospheric gases, it prevented substantial amounts of sunlight from reaching Earth’s surface, eventually reducing the average global temperature by as much as 3 °C.

c-14 is carbon-14, or radiocarbon.   it is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.