"I learnt this concept in physics."
Translation:Tôi đã học khái niệm này trong môn vật lý.
wrong spelling for simple past of the verb- you meant to say "learned". "learnt" is the past participle and only used after "to have" for example "I have learnt"
I thought that both past simple and pp form of 'learn' have two different spelling that are -ed and -t.