1
To calculate the difference between the local times of any two places on the earth, …………. .
(a) the noon time at both the places should be known
(b) the difference in degrees of their longitudes should be known
(c) the difference in standard times of both the places should be known
(d) changes need to be made according to International Date Line.
Answer:
(b) the difference in degrees of their longitudes should be known
There are …………. time zones in the world.
(a) 360
(b) 24
(c) 100
(d) 365
Answer:
(b) 24
The earth requires 24 hours for one rotation. In one hour, ……………. .
(a) 5 longitudes will face the sun
(b) 10 longitudes will face the sun
(c) 15 longitudes will face the sun
(d) 20 longitudes will face the sun
Answer:
(c) 15 longitudes will face the sun
Indian Standard Time is …………..
(a) ahead of Greenwich Mean Time by 5 hours 30 minutes
(b) ahead of Greenwich Mean Time by 3 hours 50 minutes
(c) behind Greenwich Mean Time by 5 hours 30 minutes
(d) behind Greenwich Mean Time by 3 hours 50 minutes
Answer:
(a) ahead of Greenwich Mean Time by 5 hours 30 minutes
Question c.
The difference between the local time of any two consecutive longitudes is …………… .
(a) 15 minutes
(b) 04 minutes
(c) 30 minutes
(d) 60 minutes
Answer:
(b) 04 minutes
Answer the following questions in one sentence each:
How many longitudes pass the sun in one hour?
Answer:
15 longitudes pass the sun in one hour.
Examine the following statements and correct the incorrect ones:
In India, three standard times exist.
Answer:
Incorrect.
Correct statement: In India, one standard time exists.
Answer the following questions in one sentence each:
How much time does the earth take to complete one rotation?
Answer:
The earth takes nearly 24 hours to complete one rotation.
Answer the following questions in one sentence each:
What is the maximum number of local times that can there be in the world?
Answer:
The maximum number of local times that can be there in the world is 360.
Examine the following statements and correct the incorrect ones:
If the difference between two longitudes is of 20 degrees, the difference in their local times will be of four hours.
Answer:
Incorrect.
Correct statement: If the difference between two longitudes is of 20 degrees, the difference in their local times will be of 1 hour and 20 minutes.
If there is 3 pm at 0 degree, then what will the time at 90 E?
9 pm
If there is 5 am at 15 W, then what will the time at 60 W?
2 am
If there is 6 pm at 15 E, then what will the time at 60 W?
1 pm
If there is 8 am at 15 E, then what will the time at 90 E?
1 pm
If there is 11 pm at 60 E, then what will the time at 30 W?
5 pm
Give geographical reasons for the following:
a. The local time is decided by the noontime.
Answer:
1. When at a particular place, the sun reaches the maximum height in the sky it is assumed that almost half of the daytime is over and this time is considered 12 noon.
2. The time of a particular place as decided by the overhead position of the sun in the sky is considered as the local time of that place.
3. During the rotation of the earth, when a particular longitude comes exactly in front of the sun, it is considered as noontime (12 noon) on that longitude. This noontime is considered as local time of that longitude.
In this way, the local time is decided by the noontime.
How is the standard time of a place determined?
Answer:
1. The local time at the longitude passing through the middle of a country/ place is generally considered as a standard time of that country/place.
2. If the difference between the local time at the extreme east and west longitude passing through a country is less than one or two hours, one standard time is considered for a country. Thus, there exists only one standard time in a country having comparatively less longitudinal (east-west) extent.
3. If the difference between the local time at the extreme east and west longitude passing through a country is more than one or two hours, more than one standard time zones are considered for a country. Thus, there exists more than one standard time zones in a country having comparatively more longitudinal (east-west) extent.
Give geographical reasons for the following:
The local time at Greenwich is considered to be the International Standard Time.
Answer:
For this purpose, the local time at Greenwich is considered to be the International Standard Time.
Give geographical reasons for the following:
Canada has 6 different standard times.
Answer:
Therefore, it is not practically helpful to consider single standard time in Canada. Therefore, for synchronizing the routine activities in the country, Canada has 6 different standard times.
Give geographical reasons for the following:
The standard time of India has been decided by the local time at 82°30′ E longitude.
Answer: