How effective were fire arrows really?

by NiceIsland

I remember getting a question wrong on a test for having written that fire arrows actually weren't effective and need confirmation,

MaesterMagoo

I am not looking to prevent others from answering but /u/freevoulous answered this a while ago.

https://www.reddit.com/r/AskHistorians/comments/26wopt/just_how_common_were_flaming_arrows_in_medieval/