Why there is a time lag of 2 hrs from Gujarat to Arunachal Pradesh. But still, our watches show the same time? The local time of a place is calculated on the basis of the overhead sun. The sun rises 2 hrs earlier in Arunachal Pradesh in the east as compared to Gujarat in the west.
Explanation: The sun rises in the east as the sun is 4 minutes ahead of every meridian while going from west to east. Kutch in Gujarat is located at 6908\’ longitude while Arunachal Pradesh is at 97025\’ East. This creates a difference of almost 300 longitudes away from each other and a time lag of 2 hrs. (i.e. 30*4=120 minutes= 2hrs)
Watches show the same time because the time lag along the standard meridian of India (82030\’E) passing through Mirzapur in Uttar Pradesh is taken as standard time.
Hence the watches show the same time.