Geography

 Lessons on 01/05/2024

Objectives: Examine the significance of latitudes and longitudes to locate and find the time of

places.

24 hours = 360 o  longitude

1 hour = 360 o ÷24 =15 o

60 minutes = 15 o (or)

60 ÷15 = 4 minutes

1. Therefore, 1 o = 4 minutes

Important notes to remember.

1. Time at any place can be calculated if its longitude and the GMT are provided.

2. All places on the same meridian have the same time.

3. Time in places in the East is ahead/ more than that of places in the West.

4. Time in places in the West is behind/less than that of places in the East.

5. 1 o  of longitude makes a difference of 4 minutes.

6. When you travel east, add 4 minutes for every one degree of longitude.

 (Rule: East Gain or Add)

When you travel East, add 4 minutes for every one degree of longitude

(Rule: West loss or subtract)

When you travel West, subtract 4 minutes for every one degree of longitude

If the given longitude is in the same direction, it should be subtracted.

 (East and East: Subtract)

(West and West: Subtract)

(West and East: Add)

If the given longitude is in a different direction or hemisphere, it should be added.

(East and West: Add)

Smaller longitudinal values will be subtracted from bigger values.

Procedure to calculate the time

1. Find the difference in longitude or numbers of longitude.

2. 1 o = 4 Minutes (fact)

3. Convert degree into minutes.

4. Convert minutes into hours.

5. Addition of time.

6. Subtraction of time.

River System

Stages of River

Maps of the River system in Bhutan