Maharashtra Board Class 8 Geography Chapter 1 Local Time and Standard Time Solutions

1. Complete the sentence by selecting the correct option:

Question a. 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
In simple words: The Earth completes a full 360-degree rotation in 24 hours. Since there are 360 longitudes, this means 15 longitudes pass under the sun's direct light every hour.

🎯 Exam Tip: Understanding the Earth's rotation speed and its relation to longitude is crucial for calculating local time differences accurately.

 

Question b. 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
In simple words: Local time is directly determined by a place's longitude. To find the time difference between two locations, you must know the difference in their longitudinal positions.

🎯 Exam Tip: Calculating time differences always starts with the longitudinal separation, as each degree of longitude corresponds to a specific time difference.

 

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
In simple words: The Earth rotates 360 degrees in 24 hours. Dividing 24 hours by 360 degrees gives 4 minutes per degree of longitude.

🎯 Exam Tip: Remember the fundamental conversion: 1 degree of longitude equals 4 minutes of time. This is a key constant in time zone calculations.

 

2. Give geographical reasons for the following:

Question 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.
In simple words: Local time is fundamentally based on the sun's position. When the sun is directly overhead at its highest point for a specific longitude, that moment is defined as 12 noon, which forms the basis for local time there.

🎯 Exam Tip: Emphasize the direct relationship between the sun's zenith position and the concept of local noon when explaining local time determination.

 

Question b. The local time at Greenwich is considered to be the International Standard Time.
Answer:
1. The International Standard Time has been decided according to 0° longitude.
2. 0° longitude passes through Greenwich, England.
3. For an international coordination, it is essential to bring compatibility between the standard times of various countries in the world.
For this purpose, the local time at Greenwich is considered to be the International Standard Time.
In simple words: The 0° longitude, which passes through Greenwich, England, was globally adopted as the Prime Meridian. Its local time serves as a universal reference point, known as Greenwich Mean Time (GMT) or Universal Standard Time (UST), to ensure consistent timekeeping and coordination across different countries worldwide.

🎯 Exam Tip: Highlight the Prime Meridian's role and the need for international coordination as the primary reasons for Greenwich's significance in global timekeeping.

 

Question c. The standard time of India has been decided by the local time at 82°30′ E longitude.
Answer:
1. With respect to the longitudinal extent, 82°30'E longitude passes through the middle of India.
2. The difference between the local time at 82°30′E longitude and the local time at the extreme east and west longitude passing through India is not more than one hour.
Therefore, the standard time of India has been decided by the local time at 82°30′E longitude.
In simple words: India's vast east-west longitudinal extent means local times vary significantly. To avoid confusion, a central longitude of 82°30′ E was chosen, as it passes roughly through the middle of the country, ensuring that the maximum time difference from this standard time to any other part of India is manageable (less than an hour).

🎯 Exam Tip: When discussing India's standard time, mention both the specific longitude (82°30' E) and the practical benefit of minimizing time variation across the country.

 

Question d. Canada has 6 different standard times.
Answer:
1. The longitudinal extent of Canada is between 52°37′ W and 141° W.
2. Thus, the difference between the extreme east and west longitude passing through Canada is of 88 degrees.
3. The difference between the local time at extreme east and west longitude passing through Canada is of 352 minutes i.e. 5 hours and 52 minutes.
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.
In simple words: Canada spans a very wide range of longitudes, leading to a significant difference of almost six hours between its easternmost and westernmost points. To effectively synchronize daily activities and maintain order across such a vast expanse, Canada uses multiple standard time zones instead of a single one.

🎯 Exam Tip: For countries with large longitudinal extents, explain that multiple time zones are adopted to manage substantial local time differences and facilitate daily operations.

 

3. Answer in brief:

Question a. If it is 12 noon at 60° E longitude, then explain what would be the time at 30° W longitude.
Answer:
1. The difference between 60° E longitude and 30° W longitude will be of 90 degrees.
(The difference of 60 degrees between 0° and 60° E + the difference of 30 degrees between 0° and 30° W = 90 degrees.)
2. Difference in local time = 90 × 4
= 360 minutes.
= 360 minutes ÷ 60 minutes = 6 hours.
3. Longitudes lying to the east of any longitude are ahead of the time of that longitude while those lying to the west are behind.
4. Therefore, if it is 12 noon at 60° E longitude, then it would be 6 a.m. at 30° W longitude, (behind by 6 hours)
In simple words: To find the time at 30° W when it's 12 noon at 60° E, first calculate the total longitudinal difference, which is 90 degrees. Since each degree is 4 minutes, the total time difference is 360 minutes or 6 hours. Because 30° W is to the west of 60° E, the time will be earlier, so 6 hours before 12 noon is 6 a.m.

🎯 Exam Tip: Clearly show each step of the calculation, from finding the longitudinal difference to converting it into hours and applying the east-ahead/west-behind rule.

 

Question b. 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.
In simple words: Standard time is determined by choosing a central longitude for a country or region, whose local time then becomes the uniform time for that entire area. This is especially important for large countries, where a single standard time helps avoid confusion caused by significant differences in local times from east to west.

🎯 Exam Tip: Explain that standard time balances the need for uniformity across a region with the actual solar time variations, often by selecting a meridian that minimizes the deviation for most parts of the country.

 

Question c. A football match being played at Sao Paulo, Brazil started in India at 6 a.m. IST. Explain what would be the local time at Sao Paulo?
Answer:
1. Statement: For any longitude lying to the west of particular longitude, the local time decreases by 4 minutes for every longitude. (Sao Paulo is located to the west of India)
2. The difference between the longitudes of Sao Paulo and India = 127°30′.
3. Difference in local time = 127.5 × 4
= 510 minutes.
= 510 minutes ÷ 60 minutes
= 8 hours 30 minutes.
4. Thus, if it is 6 a.m. at India, it would be 9.30 p.m. of the previous day at Sao Paulo. Therefore, if a football match being played at Sao Paulo, Brazil started in India at 6 a.m. IST, the local time at Sao Paulo would be 9.30 p.m. of previous day.
In simple words: Sao Paulo is significantly west of India, meaning its time is much earlier. The longitudinal difference is 127.5 degrees, leading to an 8 hour and 30 minute time difference. Therefore, if a match starts at 6 a.m. IST, it would be 8 hours and 30 minutes earlier in Sao Paulo, placing the start time at 9:30 p.m. on the *previous* day.

🎯 Exam Tip: For complex time difference problems, clearly state the longitudinal positions, calculate the total difference in degrees, convert to minutes/hours, and then apply the east/west rule carefully, noting any day changes.

 

4. Complete the following table:
If it is 10 pm on 21st June at Prime Meridian, write the dates and time at A, B and C in the following table:
(Note: The answer is given directly.)

Question 1.

Place	Longitude	Date	Time
A	120° E
B	160° W
C	60° E

Answer:

Place	Longitude	Date	Time
A	120° E	22nd June	6 a.m.
B	160° W	21st June	11.20 a.m.
C	60° E	22nd June	2 a.m.

In simple words: Starting from 10 p.m. on June 21st at the Prime Meridian (0°), moving east (A & C) means adding time and possibly advancing a day, while moving west (B) means subtracting time and potentially remaining on the same day or going back one. Each 15 degrees of longitude represents one hour.

🎯 Exam Tip: When filling out such tables, consistently apply the 4 minutes per degree rule, remembering that east is ahead in time and west is behind, and meticulously track day changes across the International Date Line.

 

5. Write the situation of place A shown in these diagrams in the boxes below them:

Question 1. Write the situation of place A shown in these diagrams in the boxes below them
(i) Sunrise
(ii) Midnight
(iii) Noon
(iv) Sunset

ℹ️ चित्र व्याख्या (Diagram Explanation): यह एक चार-भाग वाला आरेख है जो पृथ्वी की घूर्णन गति और सूर्य के सापेक्ष 'A' नामक स्थान पर दिन के विभिन्न समयों (आधी रात, सूर्यास्त, सूर्योदय, दोपहर) को दर्शाता है। प्रत्येक भाग में पृथ्वी का एक गोलाकार दृश्य है जिसमें एक 'N.P.' (उत्तरी ध्रुव) और 'A' नामक एक बिंदु दिखाया गया है, साथ ही सूर्य को प्रकाश के स्रोत के रूप में दर्शाया गया है जो पृथ्वी के कुछ हिस्से को रोशन कर रहा है। आरेख दिखाता है कि जैसे-जैसे पृथ्वी घूमती है, स्थान 'A' सूर्य के सामने कैसे आता और जाता है, जिससे दिन और रात का चक्र पूरा होता है।
Answer:(1) Midnight
(2) Sunset
(3) Sunrise
(4) Noon
In simple words: The diagrams illustrate the Earth's rotation relative to the sun. 'Midnight' occurs when location A is directly opposite the sun, 'Sunset' as A moves away from the sun's direct light, 'Sunrise' as A begins to face the sun, and 'Noon' when A is directly facing the sun.

🎯 Exam Tip: To interpret such diagrams, understand that midnight is on the side furthest from the sun, noon is on the side directly facing it, and sunrise/sunset are at the terminator (the line between light and dark).

 

Let's recall:

Question 1. Why does the duration of day and night keep changing?
Answer:
The duration of day and night keeps changing as the earth is tilted at an angle of 23.5 degrees.
In simple words: The Earth's axis is tilted at 23.5 degrees relative to its orbital plane around the sun. This tilt, combined with the Earth's revolution, causes different parts of the planet to receive varying amounts of sunlight throughout the year, leading to changes in the duration of day and night.

🎯 Exam Tip: Always link the changing duration of day and night directly to the Earth's axial tilt and its revolution around the sun.

 

Question 2. How many longitudes can be drawn on a world map keeping an interval of 1° each?
Answer:
360 longitudes can be drawn on a world map keeping an interval of 10 each.
In simple words: A full circle around the Earth is 360 degrees. Therefore, if each longitude is drawn at a 1-degree interval, you can draw exactly 360 longitudes to cover the entire globe.

🎯 Exam Tip: Remember that a sphere has 360 degrees, which directly translates to the maximum number of longitudes at 1-degree intervals.

 

Question 3. The apparent movement of the sun from east to west is a result of what?
Answer:
The apparent movement of the sun from east to west is a result of the rotation of the earth from west to east.
In simple words: Although it seems like the sun moves across the sky from east to west, this is an illusion. The actual cause is the Earth's rotation on its axis from west to east, making the sun appear to move in the opposite direction.

🎯 Exam Tip: This is a common misconception; clarify that apparent motion is due to Earth's rotation, not the sun's actual movement around Earth.

 

Question 4. What is the direction of the rotation of the earth?
Answer:
The direction of the rotation of the earth is from west to east.
In simple words: The Earth spins on its axis in a counter-clockwise direction when viewed from above the North Pole, which means it rotates from west to east. This rotation is what causes the cycle of day and night.

🎯 Exam Tip: Emphasize "west to east" as the correct direction of Earth's rotation to avoid confusion with the sun's apparent motion.

 

Question 5. While the earth rotates, how many longitudes face the sun daily?
Answer:
While the earth rotates, 360 longitudes face the sun dally.
In simple words: As the Earth completes one full rotation in 24 hours, all 360 longitudes pass through the illuminated side of the Earth, meaning each one experiences daylight at some point during the day.

🎯 Exam Tip: Connect the 360-degree rotation of the Earth to the fact that all 360 longitudes eventually face the sun in a 24-hour cycle.

 

Question 6. At which longitude does the date change?
Answer:
The date changes at 1800 longitude.
In simple words: The International Date Line, located at approximately 180° longitude, is the imaginary line where the date changes. Crossing it from west to east moves you back a day, while crossing it from east to west moves you forward a day.

🎯 Exam Tip: Make sure to specifically name the International Date Line when discussing the 180° longitude as the point of date change.

 

Question 7. How was the time measured in olden days?
Answer:
In olden days, the time was measured with the help of the natural events of sunrise and sunset and the instruments like Ghatikapaatra, sand timer, etc.
In simple words: In the past, people relied on natural phenomena like sunrise, sunset, and the sun's position in the sky to tell time. They also used simple devices such as sundials, water clocks (Ghatikapaatra), and sand timers to track the passage of time.

🎯 Exam Tip: Mention both natural observations (sun's movement) and early time-measuring instruments (Ghatikapaatra, sand timer) for a complete answer.

 

Question 8. In present tunes, what are the instruments used for time measurement?
Answer:
In present times, the instruments like watches, calendars, etc. are used for time measurement.
In simple words: Modern timekeeping relies on precise mechanical and electronic devices such as watches (wristwatches, wall clocks), atomic clocks, and digital calendars to measure and track time accurately.

🎯 Exam Tip: Focus on modern, precise instruments like watches and calendars that are commonly used today for time measurement.

 

Activity:

Question 1. Look for the actual granny's clock in Shri Acharya Atre's poem: "Aajiche Ghadyal" (Granny's clock). Look for this poem on the internet or in reference book.
In simple words: This question encourages students to explore traditional literary references to timekeeping, specifically a poem about a "granny's clock." It's an assignment to research cultural depictions of time.

🎯 Exam Tip: This is an activity-based question; a student should describe the poem's context and what the "granny's clock" represents if asked to write about it.

 

Question 2. Find out the velocity of the earth's rotation in km/hour.
In simple words: This question prompts students to calculate the speed at which the Earth rotates. They would need to find the Earth's circumference at the equator and divide it by the 24 hours it takes to complete one rotation to get the velocity in km/hour.

🎯 Exam Tip: For calculation-based questions, show the formula (circumference/time) and the values used for circumference and rotation period to arrive at the answer.

 

Class 8 Geography Chapter 1 Local Time And Standard Time Additional Important Questions and Answers

Complete the sentence by selecting the correct option:

Question a. There are ....... time zones in the world.
(a) 360
(b) 24
(c) 100
(d) 365
Answer: (b) 24
In simple words: Globally, the Earth is divided into 24 main time zones, each approximately 15 degrees of longitude wide, corresponding to one hour of time difference.

🎯 Exam Tip: Recall that the 24-hour day naturally leads to 24 primary time zones, based on 15 degrees of longitude per hour.

 

Question b. 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
In simple words: India's standard meridian is 82°30′ E, and since each degree represents 4 minutes, this places India 5 hours and 30 minutes ahead of Greenwich Mean Time (GMT).

🎯 Exam Tip: Memorize the specific time difference between IST and GMT (5 hours 30 minutes ahead) as it's a frequently tested fact.

 

Examine the following statements and correct the incorrect ones:

Question 1. Mumbai is located at 73° E longitude.
Answer:
Correct.
In simple words: This statement is accurate; Mumbai's geographical position is indeed around 73° E longitude.

🎯 Exam Tip: For correctness statements, simply state "Correct" or "Incorrect" followed by the correct version if needed.

 

Question 2. In India, three standard times exist.
Answer:
Incorrect.
Correct statement: In India, one standard time exists.
In simple words: Despite its large size, India follows a single standard time (IST) based on 82°30′ E longitude to maintain uniformity across the country.

🎯 Exam Tip: Clearly state "Incorrect" and then provide the accurate information as the "Correct statement."

 

Question 3. 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.
In simple words: Since each degree of longitude accounts for 4 minutes of time, a 20-degree difference results in 80 minutes (20 x 4 = 80). Eighty minutes is equivalent to 1 hour and 20 minutes, not four hours.

🎯 Exam Tip: Always perform the calculation (degrees x 4 minutes/degree) and then convert minutes to hours and minutes to ensure accuracy in time difference questions.

 

Answer the following questions in one sentence each:

Question 1. Think about it.

Question a. 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.
In simple words: Since there are 360 degrees of longitude around the Earth, and each degree can theoretically have its own distinct local time based on the sun's position, there can be up to 360 unique local times.

🎯 Exam Tip: The maximum number of local times corresponds directly to the number of longitudinal degrees on Earth.

 

Question b. How many longitudes pass the sun in one hour?
Answer:
15 longitudes pass the sun in one hour.
In simple words: The Earth rotates 360 degrees in 24 hours. Dividing 360 by 24 gives 15 degrees, meaning 15 longitudes pass directly under the sun's gaze every hour.

🎯 Exam Tip: This is a direct calculation from the Earth's rotation: 360 degrees / 24 hours = 15 degrees/hour.

 

Question 2. How much time does the earth take to complete one rotation?
Answer:
The earth takes nearly 24 hours to complete one rotation.
In simple words: The Earth completes a full spin on its axis, known as one rotation, in approximately 24 hours, which defines a standard day.

🎯 Exam Tip: State the common knowledge fact that Earth's rotation period is approximately 24 hours.

 

Question 3. What is meant by the local time of a place?
Answer:
When the sun is directly overhead at a particular place, it is considered as noon at that place and that time is considered as a local time of that place.
In simple words: Local time refers to the time at a specific location, determined by the sun's position relative to that longitude. When the sun is at its highest point in the sky at a given place, it's considered 12 noon, and this forms the basis of that location's local time.

🎯 Exam Tip: Define local time by its direct relation to the sun's overhead position, which marks local noon.

 

Solve the following:

1. Try this:

Question A. Mashad, a town in Iran, is located on the 60° E longitude. When it is 12 noon at Greenwich, calculate the local time of Mashad town.
Answer:
1. Statement: As we move towards the east of the Prime Meridian, the local time increases by four minutes for every longitude. (Mashad is located to the east of Greenwich.)
2. The difference between the longitudes of Greenwich and Mashad = 60°.
3. Difference in local time = 60 × 4
= 240 minutes.
= 240 minutes ÷ 60 minutes
= 4 hours. '
4. Therefore, when it is noon at Greenwich, it would be 4 p.m. at Mashad. (Ahead of Greenwich Mean Time by 4 hours.)
In simple words: Mashad is 60° East of Greenwich. Since each degree east adds 4 minutes, the total time difference is 60 x 4 = 240 minutes, or 4 hours. As Mashad is to the east, its time is ahead. So, if it's 12 noon at Greenwich, it would be 4 p.m. in Mashad.

🎯 Exam Tip: For time calculations, clearly identify the reference point (Greenwich), the target location's longitude, calculate the total time difference, and correctly apply "ahead" for east and "behind" for west.

 

Question B. Manaus city in Brazil is located on 60° W longitude. What would be the local time at Manaus when it is 12 noon at Greenwich?
Answer:
1. Statement: As we move towards the west of the Prime Meridian, the local time decrease by four minutes for every longitude. (Manaus is located to the west of Greenwich.)
2. The difference between the longitudes of Greenwich and Manaus = 60°.
3. Difference in local time = 60 × 4
= 240 minutes.
= 240 minutes ÷ 60 minutes
= 4 hours.
4. Therefore, when it is noon at Greenwich, it would be 8 a.m. at Manaus. (Behind Greenwich Mean Time by 4 hours.)
In simple words: Manaus is 60° West of Greenwich. Because each degree west subtracts 4 minutes, the total time difference is 60 x 4 = 240 minutes, which is 4 hours. Since Manaus is to the west, its time is behind Greenwich. So, if it's 12 noon at Greenwich, it would be 8 a.m. in Manaus.

🎯 Exam Tip: Remember that locations to the west of the Prime Meridian are behind in time. Calculate the difference and subtract from the Greenwich time.

 

2. Can you tell?

Question A. Mumbai is located at 73° E longitude. Kolkata is located at 88° E longitude. Find the difference between the longitudes of these two cities.
Answer:
Mumbai is located at 73° E longitude. Kolkata is located at 88° E longitude. Therefore, the difference between the longitudes of these two cities would be of (88 – 73 = 15) 15°.
In simple words: To find the longitudinal difference between two places on the same side of the Prime Meridian, simply subtract the smaller longitude from the larger one. For Mumbai (73° E) and Kolkata (88° E), the difference is 15 degrees.

🎯 Exam Tip: When both locations are on the same side (both East or both West), calculate the difference by simple subtraction of their longitudes.

 

Question B. If the local time at Mumbai is 3 p.m. then what would be the local time at Kolkata?
Answer:
1. Statement: For any longitude lying to the east of particular longitude, the local time increases by 4 minutes for every longitude.
2. The difference between the longitudes of Mumbai and Kolkata = 15°.
3. Difference in local time = 15 × 4
= 60 minutes.
= 60 minutes -r- 60 minutes = 1 hour.
4. Kolkata is located to the east of Mumbai. Therefore, if it is 3 p.m. at Mumbai, then it would be 4 p.m. at Kolkata. (ahead by 1 hour)
In simple words: Kolkata is 15 degrees east of Mumbai. Since each degree corresponds to 4 minutes, the time difference is 15 x 4 = 60 minutes, which is 1 hour. Because Kolkata is to the east, its time is ahead. So, if it's 3 p.m. in Mumbai, it would be 4 p.m. in Kolkata.

🎯 Exam Tip: After finding the longitudinal difference, convert it to time, and then correctly add the time for locations to the east or subtract for locations to the west.

 

Answer the following questions in brief:

Question a. Give brief information about the Indian Standard Time.
Answer:
1. The Indian Standard Time (IST) is calculated on the basis of 82°30′E longitude, passing through Mirzapur, near Allahabad in Uttar Pradesh.
2. With respect to longitudinal extent, 82°30' E longitude passes through the middle of India.
3. When the sun is directly overhead on this longitude, it is considered that it is 12 noon at every place in India. Thus, the local time at 82°30′E longitude is considered as the Standard time of India.
4. The difference between the local time at 82°30′ E longitude and the local time at the extreme east and west longitude passing through India is not more than one hour.
In simple words: Indian Standard Time (IST) is the official time zone for India, based on the local time at 82°30′ E longitude, which passes near Mirzapur in Uttar Pradesh. This central meridian was chosen because it minimizes the time difference across the country's vast longitudinal spread to less than an hour, providing a uniform time for all of India.

🎯 Exam Tip: Be precise with the standard meridian (82°30′ E) and explain why it was chosen – to provide a unified time across India, managing its longitudinal extent.

 

Question b. Give brief information about Universal Standard Time.
Answer:
1. As the standard time is essential for synchronizing routine activities in a country with comparatively more j longitudinal extent, the universal standard i time is essential for an international coordinating between the countries in the world.
2. For this purpose, the local time at Greenwich (Greenwich Mean Time) in England is considered to be the International/Universal Standard Time (UST).
3. With reference to GMT, the differences in standard times of various countries in the world are calculated.
4. The Indian Standard Time is ahead of GMT by 5 hours and 30 minutes. For example, if it is 12 noon at Greenwich, then it would be 5.30 p.m. in India.
In simple words: Universal Standard Time (UST), also known as Greenwich Mean Time (GMT), is the world's primary time reference based on the local time at the Prime Meridian (0° longitude) in Greenwich, England. It serves as a global baseline for coordinating time across all countries, allowing for consistent calculations of individual time zones.

🎯 Exam Tip: Define UST/GMT by its location (Greenwich, 0° longitude) and its purpose: global synchronization and a reference for all other time zones.

 

Give geographical reasons for the following:

Question a. In the countries with larger area, it is convenient to use one standard time instead of more than one local times.
Answer:
1. In the countries with larger area, much difference between the local times at extreme east and west longitude passing through the countries is found.
2. In such countries, if more than one local times are followed, it could lead to lots of confusion and chaos.
3. For example, if more than one local times are followed, it will become difficult to synchronize the timetable of railways, airways, etc. Therefore, in countries with comparatively larger area, it is convenient to use one standard time instead of more than one local times.
In simple words: For countries with a large longitudinal spread, local times can vary significantly. Adopting a single standard time across the entire country simplifies daily life, prevents confusion in scheduling activities like transportation and business, and promotes national unity in timekeeping, even if it means slight deviations from actual solar time at the extremes.

🎯 Exam Tip: Focus on the practical benefits of a single standard time in large countries: reducing confusion, simplifying coordination (e.g., transport), and avoiding chaos in daily routines.

 

Study the following map/figure/graph and answer the following questions:

1. Can you tell?
Study the figure 1.3 given on page 4 of the textbook and answer the following questions:

 

Question 1. Between which longitudes does the region experience daytime?
Answer: The region shown between 90° W and 90° E in the figure experiences daytime.
In simple words: The area on Earth between 90 degrees West longitude and 90 degrees East longitude is currently experiencing daylight.

🎯 Exam Tip: Understanding the Earth's rotation and its effect on longitude and daylight is crucial for geographical time calculations.

 

Question 2. Which longitudes experience noon and the midnight respectively?
Answer: 0° longitude and 180° longitude experience noon and the midnight respectively.
In simple words: The 0° longitude (Prime Meridian) experiences noon when directly facing the sun, while the 180° longitude experiences midnight at the same time.

🎯 Exam Tip: Remember the relationship between the Prime Meridian, International Date Line, and the solar positions for noon and midnight.

 

Question 3. Edward from New Orleans is on which longitude?
Answer: Edward from New Orleans is on 90° W longitude.
In simple words: Edward, residing in New Orleans, is located at the 90° West longitude.

🎯 Exam Tip: Identifying specific locations on a map based on their longitudinal coordinates is a fundamental skill in geography.

 

Question 4. What is the time at Accra city?
Answer: It is 12 noon at Accra city.
In simple words: Accra city is currently experiencing 12 noon.

🎯 Exam Tip: Local time is often determined by the sun's position, with 12 noon indicating the sun is at its highest point.

 

Question 5. At the same time, what is Sharad from Patna and Yakaito from Japan doing? What time is it in these cities?
Answer: At the same time, Sharad is returning home from school and Yakaito from Japan is preparing for the night's sleep. At the same time, it is 5.30 p.m. at Patna and 9.20 p.m. at Japan.
In simple words: When it's noon in Accra, Sharad in Patna is coming home from school at 5:30 p.m., and Yakaito in Japan is preparing for bed at 9:20 p.m.

🎯 Exam Tip: This question tests understanding of time differences across various longitudes and continents.

 

Question 6. Select any one longitude. Calculate the local time of the longitudes lying 1° to the west and east of this longitude.
Answer:
1. The selected longitude: 60° E. The local time of the selected longitude is 4 p.m.
2. The local time of the longitude lying 1° to the west of the selected longitude (59° E) will be 3.56 p.m.
3. The local time of the longitude lying 1° to the east of the selected longitude (61° E) will be 4.04 p.m.
In simple words: If it is 4 p.m. at 60° E longitude, then 1° to its west (59° E) it would be 3:56 p.m., and 1° to its east (61° E) it would be 4:04 p.m., due to the Earth's rotation.

🎯 Exam Tip: Remember that each degree of longitude corresponds to a 4-minute time difference (east is ahead, west is behind).

 

Question 1. Considering the longitudinal extent of India, how many longitudes with a difference of 1° can be drawn on a map?
Answer: Considering the longitudinal extent of India, 29 longitudes with a difference of 1° can be drawn on a map.
In simple words: Based on India's east-west spread, approximately 29 lines of longitude can be drawn across the country at one-degree intervals.

🎯 Exam Tip: Knowing the longitudinal extent of a country helps in understanding its time zones and time differences.

 

Question 2. By how many minutes do two consecutive longitudes differ?
Answer: Two consecutive longitudes differ by 4 minutes.
In simple words: There is a 4-minute time difference between any two adjacent lines of longitude.

🎯 Exam Tip: This 4-minute rule per degree of longitude is fundamental for calculating local and standard times globally.

 

Question 3. What is the value of degrees of longitude at Mirzapur?
Answer: The value of longitude at Mirzapur is 82°30′.
In simple words: Mirzapur is located at 82°30′ East longitude, which is used as India's standard meridian.

🎯 Exam Tip: Mirzapur's longitude (82°30′ E) is significant as it defines the Indian Standard Time (IST).

 

Question 4. If it is 8 a.m. at 82°30′ E, what would be the time in their clocks at the following places: Jammu, Madurai, Jaisalmer, Guwahati.
Answer: If it is 8 a.m. at 82°30′ E, it would be 8 a.m. in their clocks at Jammu, Madurai, Jaisalmer, Guwahati.
In simple words: Because India uses a single standard time based on 82°30′ E longitude, all places within India, like Jammu, Madurai, Jaisalmer, and Guwahati, would show the same time of 8 a.m.

🎯 Exam Tip: Understand that countries with one standard time apply that time universally across their territory, irrespective of their local longitudinal variations.

 

Question 5. Though the distance between them is more why doesn't the standard time differ in these places?
Answer: In India, the time at 82°30′ E is considered as standard time of India and therefore the same time will be considered everywhere in India. Therefore, though the distance between them is more, the standard time doesn't differ in these places.
In simple words: Standard time in India is uniformly applied across the country, using the 82°30′ E longitude as the reference, which means all regions follow the same clock time regardless of their specific local solar time differences.

🎯 Exam Tip: The adoption of a single standard time by large countries simplifies coordination but can lead to noticeable differences between local solar time and clock time at the extremities.

 

Question 1. At the poles, sunrise occurs on one equinox and sunsets on the next equinox. If you happen to be at any of the poles during this time, then what would be the route of the sun in the daytime?
Answer: At the poles, sun rises on one equinox and sets on the next equinox. If we happen to be at any of the poles during this time, then the following would be the route of the sun in the daytime:
(A) North Pole:
1. The sun will rise at the North Pole approximately on March 21.
2. Approximately, from March 21 to June 21, the sun will rise higher in the sky with each advancing day. It will reach the maximum height approximately on June 21. Approximately, from June 21 to September 21, the sun will start sinking towards the horizon in the sky with each advancing day.
3. The sun will set at the North Pole approximately on September 21.
(B) South Pole:
1. The sun will rise at the South Pole approximately on September 21.
2. Approximately, from September 21 to December 21, the sun will rise higher in the sky with each advancing day. It will reach the maximum height approximately on December 21.
3. Approximately, from December 21 to March 21, the sun will start sinking towards the horizon in the sky with each advancing day.
4. The sun will set at the South Pole approximately on March 21.
In simple words: At the poles, the sun appears above the horizon for six months, slowly rising higher until the summer solstice and then gradually sinking until the equinox when it sets, completing a cycle of continuous daylight.

🎯 Exam Tip: This phenomenon at the poles is a direct result of the Earth's axial tilt and its revolution around the sun, causing extreme seasonal variations in daylight hours.

 

Question 2. On which day, would the sun appear at the highest point in the sky?
Answer:
1. On the North Pole, approximately on June 21, the sun would appear at the highest point in the sky.
2. On the South Pole, approximately on December 21, the sun would appear at the highest point in the sky.
In simple words: At the North Pole, the sun reaches its highest point around June 21 (summer solstice), and at the South Pole, it's highest around December 21 (winter solstice in the Northern Hemisphere).

🎯 Exam Tip: The solstices mark the days when the sun reaches its northernmost or southernmost declination, resulting in the longest daylight hours for the respective hemisphere.

 

ℹ️ चित्र व्याख्या (Diagram Explanation): यह एक तालिका है जिसमें दिन के अलग-अलग समय जैसे 'Sunrise', 'Sunset', 'Noon' और 'Midnight' दिए गए हैं। छात्रों को ऐसे समय की पहचान करनी है जिन्हें घड़ी का उपयोग किए बिना बताया जा सकता है। तालिका दर्शाती है कि 'Sunrise', 'Sunset' और 'Noon' को बिना घड़ी के समझा जा सकता है, जबकि 'Midnight' भी। यह अभ्यास छात्रों की प्राकृतिक समय के संकेतों को समझने की क्षमता का परीक्षण करता है।

Question 1. Tick ✓ the time in the boxes which you can tell without using clock.
Answer:
Sunrise ☐
Sunset ☐
Noon ✓
Midnight ✓
(Note: The answer is given directly.)
In simple words: You can generally tell if it's noon or midnight without a clock by observing the sun's position (highest in the sky for noon, completely absent for midnight).

🎯 Exam Tip: This question emphasizes understanding natural phenomena for time telling, a concept often used in historical contexts of time measurement.

 

Question 1. If it is 8 a.m. in India, what is the time in Greenwich?
Answer: If it is 8 a.m. in India, it would be 2.30 a.m. in Greenwich.
In simple words: India's time (IST) is 5 hours and 30 minutes ahead of Greenwich Mean Time (GMT), so if it's 8 a.m. in India, it would be 2:30 a.m. in Greenwich.

🎯 Exam Tip: Always remember that IST is GMT + 5 hours 30 minutes when calculating time differences between India and the Prime Meridian.

 

Question 2. When it is 2 p.m. in India, in which countries would it be 2 p.m. exactly?
Answer: When it is 2 p.m. in India, it would be 2 p.m. exactly in Sri Lanka.
In simple words: If it's 2 p.m. in India, it would also be 2 p.m. in Sri Lanka because both countries share the same standard time zone (IST).

🎯 Exam Tip: Countries in the same time zone, or those that have adopted the same standard meridian, will show identical clock times.

 

Question 3. When it is 9 a.m. in India, what would be the time at 82°30′ W longitude?
Answer: When it is 9 a.m. in India, it would be 10 p.m. of the previous day at 82°30′ W longitude.
In simple words: If it's 9 a.m. in India (82°30′ E), at the opposing 82°30′ W longitude, it would be 10 p.m. on the previous day, due to the significant longitudinal difference and crossing the International Date Line mentally.

🎯 Exam Tip: Calculating time across hemispheres requires careful consideration of the 4-minute rule per degree of longitude and potential day changes when crossing the 180° longitude line (International Date Line).

 

Question 4. What would be the time at Prime Meridian when a new day starts at 180° longitude?
Answer: It would be 12 noon at Prime Meridian when a new day starts at 180° longitude.
In simple words: When a new day begins at midnight (00:00) at the 180° longitude (International Date Line), it is 12 noon at the Prime Meridian (0° longitude).

🎯 Exam Tip: The 180° longitude is the International Date Line; when it is midnight there, the Prime Meridian, which is 12 hours away, experiences noon.

 

Question 1. In which of the following countries, does only one standard time exist? (Mexico, Sri Lanka, New Zealand, China)
Answer: From the given countries, only one time exists in Sri Lanka, New Zealand and China.
In simple words: Among Mexico, Sri Lanka, New Zealand, and China, only Sri Lanka, New Zealand, and China use a single standard time zone across their entire territory.

🎯 Exam Tip: Countries with a smaller longitudinal extent or those that politically choose a single time zone, typically have only one standard time for simplicity.

 

Question 2. Why does a country having a large latitudinal extent have only one standard time?
Answer: The places lying on the same longitude have the same local time. Therefore, a country having a large latitudinal extent have only one standard time.
In simple words: A country with a large latitudinal extent, but not necessarily a large longitudinal extent, can maintain a single standard time because latitude primarily affects climate and seasons, not the local time difference based on longitude.

🎯 Exam Tip: Differentiate between latitudinal and longitudinal extent; latitudinal extent does not impact time zones, while longitudinal extent does.

 

Question 3. Which discrepancies will emerge if more than one local times, instead of one standard time are followed in a country with huge longitudinal extent?
Answer: The following discrepancies will emerge if more than one local times, instead of one standard time are followed in a country with huge longitudinal extent:
1. It will become difficult to synchronize the timetable of rail transportation, air transportation, etc. in a country.
2. It will become difficult to synchronize the timings of schools, colleges, banks, libraries, etc. in a country.
3. We will always have to adjust the time in watch as we move from one place to another in a country.
In simple words: If a country with a large east-west spread uses multiple local times instead of one standard time, it would lead to widespread confusion in transport schedules, public services, and daily life, requiring constant clock adjustments.

🎯 Exam Tip: This question highlights the practical importance of a standardized time system for national coordination and efficiency, especially in geographically large nations.

8th Std Geography Questions And Answers:

• Local Time and Standard Time Class 8 Geography Questions And Answers
• Interior of the Earth Class 8 Geography Questions And Answers
• Humidity and Clouds Class 8 Geography Questions And Answers
• Structure of Ocean Floor Class 8 Geography Questions And Answers
• Ocean Currents Class 8 Geography Questions And Answers
• Land Use Class 8 Geography Questions And Answers
• Population Class 8 Geography Questions And Answers
• Industries Class 8 Geography Questions And Answers
• Map Scale Class 8 Geography Questions And Answers
• Field Visit Class 8 Geography Questions And Answers