Question

Why does time vary from place to place?​

Answer 1

Answer:

Our earth rotates on its own axis. Due to this rotation, different parts of the earth receive different amounts of sunlight, thus causing morning, noon, evening and night. Now, if we had one time zone, then 12 pm would be noon at some places, but it would be night or evening at other places which would be inconvenient.

Answer 2

Answer:

we calculate time according to standard meridian

82°20' is taken as Indian standard time