Hi N Rahim Kumar,

IMA trains officers for a long 20 year assignment with Indian army. OTA trains men and women officers for short service commission. Also its kind of option to the people who didn't studied mathematics as their main subject during school days to get into defence forces.

if you want to spend twenty years as an officer, opt for IMA. Its in Dehradun. But if you want to experience a short term with army and then decide whether you want to extend subsequently, OTA will be your option.