1. what was the Rowlatt act?

Rowlatt Acts, (February 1919), legislation passed by the Imperial Legislative Council, the legislature of British India. The acts allowed certain political cases to be tried without juries and permitted internment of suspects without trial. Their object was to replace the repressive provisions of the wartime Defence of India Act (1915) by a permanent law. They were based on the report of Justice S.A.T. Rowlatt’s committee of 1918.  

The Rowlatt Acts were much resented by an aroused Indian public. All nonofficial Indian members of the council (i.e., those who were not officials in the colonial government) voted against the acts. Mahatma Gandhi organized a protest movement that led directly to the Massacre of Amritsar (April 1919) and subsequently to his noncooperation movement (1920–22). The acts were never actually implemented.

b.

jim crow laws were enacted in northern states.