Question

what was the main reason of the defeat of Suraj Uddin at the Battle of Plassey

Answer 1

Nawab Siraj-ud-Daulah and the British Troops met at Plassey in 1757 AD. But under the leadership of Mir Jafar the Nawab's army made no move to actually join the battle and hence Siraj-ud-Daulah was drafted.