Ought meaning? And how to use ought?

"should" and "ought to" are interchangeable.though there is slight difference- when things needed to be done "ethically" or "as a duty" "ought to" is used. तुम्हें राष्ट्रीय झंडे का सम्मान करना चाहिए you ought to respect national flag. उसे गरीबों की मदद करनी चाहिए he ought to help poors. ought to is more intimate than should.