Question

To calculate the difference between the local times of any two places on the earth,
(i) the noon time at both the places should be known(ii) the difference in degrees of their longitudes should be known(iii) the difference in standard times of both the places should be known
(iv) Changes need to be made according to International Date Line

Answer 1

To calculate time difference between two places the difference in degrees of their longitudes should be known.

This is because the earth is made up of imaginary lines called longitudes which determines the time zone of a place.

It consists of 360 longitudes which the sun covers every twenty four hours.

The time difference between one degree of longitude is 4 minutes and the degrees of longitudes is essential in finding out the time difference between two places.

Answer 2

The earth is divided into 360 longitudes, all of which are imaginary.

The difference between any two adjacent longitudes is four minutes.

Hence if we know how many longitudes lie in between two places, we can add 4 that many times and find out the difference between the local times of those two places under consideration.