Question

how did black room tragedy lead to Battle of Plassey​

Answer 1

Siraj ud Daula captured Fort William and imprisoned many Englishmen totaly there were 146 Englishmen out of that 120 died in dark room this made British angry on Siraj ud Daula and led to Battle of Plassey in 1757.

Answer 2

The only major power that stood in the way of the British East India Company from establishing their stronghold in Indian colonies was the Nawab of Bengal and his French allies. The Battle of Plassey was the victory of the Company over the Nawab establishing Company rule in Bengal.