Question

why indain standard time is 82 degree 30'e?

Answer 1

From Gujrat to Arunachal Pradesh there is a time lap of 2 hours , so the IST is 80° 30'E passing through Mirzapur (in UP)is taken as Standard time in whole country.

Answer 2

due to the spherical shape of earth thesun's light reaches at differnt time andangles. the earth is divided into many standard time lines(imaginary lines or longitude) acording to which the time is set of country .

example, in India there is an Indain standard time (IST) this is at 82'30 E (eighty two degree thirty minutes east)this set our time in India.like this there are many more lines.