Consider the following statements in case of terrestrial planets:
I. Mercury, Venus, Earth and Mars are terrestrial planets having low densities as compared to other planets.
II. They lie between the Sun and the belt of asteroids.
III. Their lower gravity can hold the escaping gases.
Which of the statements given above is/are correct?
NDA General Studies · Geography · 29 questions · 2017 to 2026
NDA Earth, solar system, latitude and time previous year questions with solutions
A small, steady corner of the General Ability Test: one to three questions a paper, never absent for long. Since 2022 one-line recall has given way to statement sets and to time arithmetic worked from longitude. Every question UPSC has set on it since 2017, solved. Grouped by the method each needs, newest first; open a question for its answer and worked solution.
29.1 The universe and the solar system (5)29.2 Shape, size and rotation of the Earth (5)29.3 Latitude, longitude and the geographical grid (7)29.4 Longitude and time: local time, standard time and the International Date Line (8)29.5 Revolution, seasons, the Sun's rays and the heat zones (4)
29.1 The universe and the solar system
1. NDA 2026 (I)
Answer and solution
Answer: (d) II only
Method. Terrestrial planets
I is wrong: the terrestrial planets (Mercury, Venus, Earth, Mars) are dense (about 3.9 to 5.5 g/cm^3), not low-density; the giant planets are low-density. II is correct: they lie between the Sun and the asteroid belt. III is wrong: their gravity is low, so they could not hold the lighter gases, which escaped. Only II is correct. (NCERT Class 11 Fundamentals ch. 2.)
2. NDA 2023 (I)
Which one of the following is the correct sequence of arrangement of the given planets in descending order of their density (in gm/cm3)?
Answer and solution
Answer: (c) Earth > Venus > Jupiter > Saturn
Method. Planetary densities
Mean densities (NASA fact sheet, as of 2026): Earth 5.51, Venus 5.24, Jupiter 1.33, Saturn 0.69 g/cm^3. So the descending order is Earth > Venus > Jupiter > Saturn. (NCERT Class 11 Fundamentals ch. 2.)
3. NDA 2021 (II)
Which one from among the following planets is largest in size?
Answer and solution
Answer: (a) Earth
Method. Planetary sizes
Equatorial diameters (NASA fact sheet, as of 2026): Earth about 12,756 km, Venus about 12,104 km, Mars about 6,792 km, Mercury about 4,879 km. Of the four, Earth is the largest, with Venus the next. (NCERT Class 11 Fundamentals, ch. 2.)
4. NDA 2021 (I)
Which one of the following planets has the highest density?
Answer and solution
Answer: (d) Earth
Method. Planetary densities
Mean densities (NASA fact sheet, as of 2026): Earth 5.51, Mercury 5.43, Venus 5.24, Jupiter 1.33 g/cm^3. Earth is the densest planet in the Solar System, and so the densest among those listed; Mercury is a close second. (NCERT Class 11 Fundamentals, ch. 2; NASA planetary fact sheet.)
5. NDA 2019 (II)
Which one of the following hypothesis/theory explains the origin of the universe?
Answer and solution
Answer: (c) Big Bang theory
Method. Origin of the universe versus origin of the Solar System
The Big Bang theory explains the origin of the universe (an expanding universe from a hot, dense initial state about 13.8 billion years ago). The Nebular hypothesis (Kant, Laplace) and the Planetesimal hypothesis (Chamberlin and Moulton) explain the origin of the Solar System; the Binary theory also concerns the Sun and planets. (NCERT Class 11 Fundamentals, ch. 2 The Origin and Evolution of the Earth.)
29.2 Shape, size and rotation of the Earth
6. NDA 2026 (II)
The Earth’s equatorial region bulges outward, but the Earth flattens slightly towards the polar regions due to the:
Answer and solution
Answer: (b) Earth’s rotational force
Method. Cause of the equatorial bulge
The Earth's rotation sets up a centrifugal effect that is greatest at the Equator, so the equatorial region bulges and the poles are flattened (oblate spheroid). Revolution does not cause it; gravity is actually slightly weaker at the equator; no oceanic mass is responsible. (NCERT Class 11 Fundamentals ch. 2; Goh Cheng Leong ch. 1.)
7. NDA 2022 (II)
Which one of the following cities of the world would represent the greatest linear velocity of rotation of the Earth?
Answer and solution
Answer: (a) Kampala, Uganda
Method. Linear speed of rotation falls with latitude
Linear velocity = (angular velocity) x (radius of the parallel), so it is greatest at the Equator (about 1,670 km/h) and falls as the cosine of latitude. Kampala lies at about 0.3 N, practically on the Equator; Madrid is about 40 N, Stockholm about 59 N and St. Petersburg about 60 N, so they are all slower. (NCERT Class 6, Motions of the Earth; Goh Cheng Leong ch. 1.)
8. NDA 2022 (I)
In a group discussion on shape and size of the Earth, three students stated the following points:
1. Student 1 : The shape of the Earth is basically an oblate spheroid.
2. Student 2 : The polar diameter of the Earth is more than the equatorial diameter.
3. Student 3 : Bulge along the equatorial region is due to revolution of the Earth.
Who among the above students is/are correct?
1. Student 1 : The shape of the Earth is basically an oblate spheroid.
2. Student 2 : The polar diameter of the Earth is more than the equatorial diameter.
3. Student 3 : Bulge along the equatorial region is due to revolution of the Earth.
Who among the above students is/are correct?
Answer and solution
Answer: (a) Student 1 only
Method. Shape of the Earth
Student 1 is correct: the Earth is an oblate spheroid (geoid), flattened at the poles and bulging at the equator. Student 2 is wrong: the equatorial diameter (about 12,756 km) is greater than the polar diameter (about 12,714 km). Student 3 is wrong: the equatorial bulge is due to the Earth's rotation (centrifugal effect), not revolution. (NCERT Class 11 Fundamentals ch. 2; Goh Cheng Leong ch. 1.)
9. NDA 2022 (I)
Inhabitants are unaware of the speed of rotation of the planet Earth because
1. the angular velocity is constant for each place on the Earth’s surface
2. the atmosphere rotates with the Earth
3. there are no nearby objects, either stationary or moving at a rate different from that of the Earth
Which of the above is/are the correct explanation(s)?
1. the angular velocity is constant for each place on the Earth’s surface
2. the atmosphere rotates with the Earth
3. there are no nearby objects, either stationary or moving at a rate different from that of the Earth
Which of the above is/are the correct explanation(s)?
Answer and solution
Answer: (d) 1, 2 and 3
Method. Why Earth's rotation is not felt
1: the rate of rotation is steady (the angular velocity is the same, about 15 degrees an hour, at every place and does not change), so we feel no acceleration. 2: the atmosphere rotates with the Earth, so there is no wind from rotation. 3: there are no nearby objects stationary or moving at a different rate to compare with. All three are valid explanations. (NCERT Class 6, Motions of the Earth; Strahler.)
10. NDA 2019 (I)
Which of the following is/are environmental effects of Rotation of the Earth?
1. Daily or diurnal rhythm in daylight and air temperature
2. Flow path of both air and water are turned consistently in a sideward direction
3. The movement of the tides
Select the correct answer using the code given below:
1. Daily or diurnal rhythm in daylight and air temperature
2. Flow path of both air and water are turned consistently in a sideward direction
3. The movement of the tides
Select the correct answer using the code given below:
Answer and solution
Answer: (c) 1, 2 and 3
Method. Effects of the Earth's rotation
1 is correct: rotation gives the alternation of day and night, hence a daily rhythm in daylight and air temperature. 2 is correct: rotation produces the Coriolis effect, which deflects the path of winds and ocean currents (to the right in the Northern, to the left in the Southern Hemisphere). 3 is correct: the daily rhythm of the tides (two high tides a day at a place) arises as the rotating Earth turns beneath the tidal bulges raised by the Moon and Sun. All three are listed as effects of rotation in Strahler's Physical Geography; NCERT Class 6, Motions of the Earth.
29.3 Latitude, longitude and the geographical grid
11. NDA 2025 (I)
Consider the following lines of Longitude and Latitude:
1. Prime Meridian
2. Tropic of Cancer
3. Equator
Which of the above lines is/are a Great Circle?
1. Prime Meridian
2. Tropic of Cancer
3. Equator
Which of the above lines is/are a Great Circle?
Answer and solution
Answer: (c) 1 and 3 only
Method. Great circle
A great circle is one whose plane passes through the centre of the Earth. The Equator is one. A meridian is half of a great circle, and the Prime Meridian together with the 180 degree meridian forms a full great circle, so meridians are counted with the great circles. The Tropic of Cancer is a small circle (parallels other than the Equator do not pass through the centre). So 1 and 3. (NCERT Class 6, Globe: Latitudes and Longitudes; Goh Cheng Leong ch. 1.)
12. NDA 2023 (II)
A geographical grid has:
1. Lines that run east to west around the globe to mark latitude
2. Lines that run north to south from north pole to south pole indicate longitude
Which of the statements given above is/are correct?
1. Lines that run east to west around the globe to mark latitude
2. Lines that run north to south from north pole to south pole indicate longitude
Which of the statements given above is/are correct?
Answer and solution
Answer: (c) Both 1 and 2
Method. Latitudes and longitudes
Lines of latitude (parallels) run east to west around the globe: statement 1 is correct. Lines of longitude (meridians) run from the North Pole to the South Pole: statement 2 is correct. Together they form the geographical grid. (NCERT Class 6, Globe: Latitudes and Longitudes.)
13. NDA 2023 (I)
Consider the following statements:
1. Distance between the longitudes becomes zero on North Pole and South Pole.
2. Distance between the longitudes is maximum on the Equator.
3. Number of longitudes is more than number of latitudes.
Which of the statements given above is/are correct?
1. Distance between the longitudes becomes zero on North Pole and South Pole.
2. Distance between the longitudes is maximum on the Equator.
3. Number of longitudes is more than number of latitudes.
Which of the statements given above is/are correct?
Answer and solution
Answer: (d) 1, 2 and 3
Method. Meridians converge; counting graticule lines
Convention used here: a meridian is counted at every degree, giving 360 longitudes (180 E, 180 W, counting 0 and 180 once), while latitudes are counted at every degree from 90 S to 90 N, giving 181 (89 N, 89 S, the Equator, and the two poles). 1: all meridians meet at the poles, so the distance between them is zero there. 2: the distance between two meridians is greatest at the Equator (about 111 km per degree) and reduces poleward. 3: 360 longitudes exceed 181 (or 179 if poles are not counted as latitudes). All three are correct. (NCERT Class 6, Globe: Latitudes and Longitudes; Goh Cheng Leong ch. 1.)
14. NDA 2022 (I)
While watching news, you hear about a place, of which you had never heard earlier. You want to know more about the place and you want to locate it on the map. Which of the following is/are required for you to be able to locate the place on the map?
Answer and solution
Answer: (c) Both longitude and latitude of the place
Method. Locating a place needs its coordinates
A place on a map is fixed by its latitude (north-south position) and longitude (east-west position); both are needed, since one alone gives only a line. Altitude is height above sea level and is not needed to locate a place on a map. (NCERT Class 6, Globe: Latitudes and Longitudes.)
15. NDA 2022 (I)
Which one of the following statements with respect to Global Positioning System (GPS) is not correct?
Answer and solution
Answer: (d) It provides information exclusively for military operations.
Method. Global Positioning System
GPS uses a network of satellites orbiting the Earth (a), fixes a position by trilateration/triangulation from several satellites (b), and gives latitude, longitude and altitude (c). (d) is not correct: GPS serves civilian uses (navigation, mapping, timing, surveying) as well as military ones.
16. NDA 2021 (II)
Which one of the following is the longest parallel of latitude?
Answer and solution
Answer: (d) Equator
Method. Parallels decrease in length from the Equator
The Equator is the longest parallel (about 40,075 km, a great circle). The Tropics and the Arctic Circle are smaller circles, shrinking poleward. (NCERT Class 6, Globe: Latitudes and Longitudes; Goh Cheng Leong ch. 1.)
17. NDA 2021 (I)
Which one of the following is the longest Latitude?
Answer and solution
Answer: (c) 0.0 degree Latitude
Method. Longest parallel of latitude
Parallels get shorter towards the poles. The Equator (0 degrees) is the largest circle of latitude (about 40,075 km); 23.5, 66.5 and 90 degrees are progressively shorter, the 90 degree 'latitude' being just a point. (NCERT Class 6, Globe: Latitudes and Longitudes; Goh Cheng Leong ch. 1.)
29.4 Longitude and time: local time, standard time and the International Date Line
18. NDA 2026 (II)
Consider the following statements:
I. The Prime Meridian is the same as the International Date Line.
II. West of the International Date Line is always a day later than east of the line.
III. The Earth turns 15° of longitude in an hour.
Which of the statements given above is/are correct?
I. The Prime Meridian is the same as the International Date Line.
II. West of the International Date Line is always a day later than east of the line.
III. The Earth turns 15° of longitude in an hour.
Which of the statements given above is/are correct?
Answer and solution
Answer: (c) II and III only
Method. Prime Meridian, Date Line, and 15 degrees per hour
I is wrong: the Prime Meridian is 0 degrees through Greenwich; the Date Line is about 180 degrees. II is correct: west of the line the date is one day ahead (later) than east of it. III is correct: 360 degrees in 24 hours = 15 degrees per hour. So II and III. (NCERT Class 6, Globe: Latitudes and Longitudes.)
19. NDA 2024 (I)
Consider the following statements regarding the International Date Line:
1. It is roughly 180° meridian, which deviates slightly East and West to avoid land areas surrounded by the Atlantic Ocean.
2. The date to the East of this line is (24 hours) earlier than to the West.
Which of the statements given above is/are correct?
1. It is roughly 180° meridian, which deviates slightly East and West to avoid land areas surrounded by the Atlantic Ocean.
2. The date to the East of this line is (24 hours) earlier than to the West.
Which of the statements given above is/are correct?
Answer and solution
Answer: (b) 2 only
Method. International Date Line
Statement 1 is wrong: the line follows roughly the 180 degree meridian and is bent to avoid land (e.g. eastern Siberia, Fiji, Tonga, Aleutians), but it runs in the Pacific Ocean, not the Atlantic. Statement 2 is correct: the date to the east of the line is one day (24 hours) behind the date to the west of it. (Goh Cheng Leong ch. 1; NCERT Class 6, Globe: Latitudes and Longitudes.)
20. NDA 2023 (I)
If it is 12 noon in New Delhi, what will be the time in London, UK?
Answer and solution
Answer: (a) 6:30 A.M.
Method. Standard time difference IST − GMT
IST = GMT + 5:30; London keeps GMT (in winter). 12:00 noon IST is 12:00 − 5:30 = 6:30 A.M. in London. (In summer, British Summer Time, GMT + 1, would give 7:30 A.M.; the options are based on GMT.) (NCERT Class 6, Globe: Latitudes and Longitudes.)
21. NDA 2022 (II)
What will happen if you are flying east across the International Date Line?
Answer and solution
Answer: (c) You will gain 24 hours
Method. Crossing the International Date Line
The line runs along about 180 degrees. Going east across it, you pass from the side whose date is a day ahead to the side whose date is a day behind, so the calendar is set back by one day (24 hours) and a date is repeated, i.e. you gain 24 hours. Going west you skip a day. (Goh Cheng Leong ch. 1; NCERT Class 6, Globe: Latitudes and Longitudes.)
22. NDA 2021 (II)
Which one of the following countries has the maximum time difference from Greenwich Mean Time (GMT)?
Answer and solution
Answer: (d) Bhutan
Method. Standard time difference from GMT
India and Sri Lanka are GMT + 5:30, Nepal GMT + 5:45, Bhutan GMT + 6:00 (Bhutan Time). The largest difference from GMT is Bhutan's 6 hours. (Standard time zones; NCERT Class 6, Globe: Latitudes and Longitudes.)
23. NDA 2021 (I)
If it is 12.00 Noon in India, on which meridian will it be 7.00 am of the same day?
Answer and solution
Answer: (a) 7.5 degree E. Longitude
Method. Local time difference of 15 degrees per hour
India's standard meridian is 82.5 E (IST = GMT + 5:30). The local time of 7:00 am is 12:00 − 7:00 = 5 hours behind, i.e. 5 x 15 = 75 degrees west of 82.5 E. 82.5 − 75 = 7.5 E. Check: at 7.5 E the local time is GMT + 0:30, and noon IST is 6:30 GMT, so the local time is 7:00 am. (NCERT Class 6, Globe: Latitudes and Longitudes.)
24. NDA 2018 (II)
Consider the following places of India:
1. Itanagar
2. Imphal
3. Agartala
4. Aizawl
Which one of the following is the correct chronological order of the above places in terms of sunrise time?
1. Itanagar
2. Imphal
3. Agartala
4. Aizawl
Which one of the following is the correct chronological order of the above places in terms of sunrise time?
Answer and solution
Answer: (b) 2-1-4-3
Method. Sunrise is earlier at greater east longitude
Taking sunrise to differ by longitude alone (the Earth rotates west to east, so the more easterly place sees the Sun first; 1 degree = 4 min), list the approximate longitudes: Imphal 93.9 E, Itanagar 93.6 E, Aizawl 92.7 E, Agartala 91.3 E. Earliest to latest sunrise: Imphal (2), Itanagar (1), Aizawl (4), Agartala (3), i.e. 2-1-4-3. Note that Imphal is slightly east of Itanagar although Itanagar is further north. (NCERT Class 6, Globe: Latitudes and Longitudes.)
25. NDA 2017 (II)
Sunrise in eastern Arunachal Pradesh would be about how many hours before the sunrise in western Gujarat?
Answer and solution
Answer: (b) Two hours
Method. Longitude gap and 4 minutes per degree
Eastern Arunachal Pradesh lies near 97 E; western Gujarat near 68 E. Gap about 29 degrees. The Earth turns 1 degree in 4 minutes, so the difference is about 29 x 4 = 116 minutes, close to 2 hours. Sunrise is earlier in the east, so Arunachal sees sunrise about two hours before Gujarat. (NCERT Class 6, Globe: Latitudes and Longitudes; India Physical Environment ch. 1.)
29.5 Revolution, seasons, the Sun's rays and the heat zones
26. NDA 2025 (II)
Arrange the following zones in ascending order in terms of their latitudinal extent on the Earth surface:
1. Equatorial zone
2. Midlatitude zone
3. Subarctic zone
4. Tropical zone
Select the answer using the code given below:
1. Equatorial zone
2. Midlatitude zone
3. Subarctic zone
4. Tropical zone
Select the answer using the code given below:
Answer and solution
Answer: (c) 1 − 4 − 2 − 3
Method. Latitudinal zones arranged from the Equator poleward (Strahler's scheme)
'Latitudinal extent' here means the latitudes over which each zone extends; ascending order is from the Equator towards the pole. In the standard scheme (Strahler, Physical Geography) the zones are: equatorial 10 S to 10 N; tropical 10 to 25 degrees; subtropical 25 to 35 degrees; midlatitude 35 to 55 degrees; subarctic 55 to 60 degrees; arctic 60 to 75; polar 75 to 90. Of the four named, the ascending order is Equatorial (1), Tropical (4), Midlatitude (2), Subarctic (3), i.e. 1-4-2-3, option (c). Read as band widths instead, no option fits (Strahler's widths give subarctic 10 < equatorial 20 < tropical 30 < midlatitude 40, i.e. 3-1-4-2, not offered), which confirms the position reading. (a), (b) and (d) place the subarctic zone before the midlatitude or tropical zones, against the poleward order. flawed: false.
Zone boundaries differ between textbooks; the solution states the scheme it uses (Strahler), the one whose zone names the question quotes.
27. NDA 2025 (I)
Which one of the following latitudes will experience a minimum angle of the Sun’s rays when it is Summer Solstice in the Northern Hemisphere?
Answer and solution
Answer: (d) Tropic of Capricorn
Method. Noon altitude of the Sun = 90 − |latitude − declination|
At the Northern Summer Solstice the declination is 23.44 N. Noon Sun angle: Tropic of Cancer 90; Equator 90 − 23.44 = 66.56; Arctic Circle (66.56 N) 90 − 43.12 = 46.88; Tropic of Capricorn (23.44 S) 90 − 46.88 = 43.12. The smallest angle among the four is at the Tropic of Capricorn (about 43 degrees), not the Arctic Circle (about 47 degrees). (NCERT Class 6, Motions of the Earth; Goh Cheng Leong ch. 1.)
28. NDA 2024 (II)
In which among the following states in India, the Sun rays are never perpendicular?
1. Bihar
2. Chhattisgarh
3. Manipur
4. Rajasthan
Select the answer using the code given below:
1. Bihar
2. Chhattisgarh
3. Manipur
4. Rajasthan
Select the answer using the code given below:
Answer and solution
Answer: (b) 1 and 3
Method. Sun overhead only between the Tropics
The Sun's vertical rays occur only between 23.5 N and 23.5 S, so places north of the Tropic of Cancer never get a vertical Sun. Bihar (about 24.3 N to 27.5 N) and Manipur (about 23.8 N to 25.7 N) lie wholly north of the Tropic. Chhattisgarh (extends south to about 17.8 N) and Rajasthan (extends south to about 23.1 N) are crossed by the Tropic of Cancer and have parts south of it. So 1 and 3. (NCERT India Physical Environment ch. 1.)
29. NDA 2017 (II)
The shortest day length that occurs in the Northern hemisphere is on
Answer and solution
Answer: (d) 22nd December
Method. Sun's declination and day length in the Northern Hemisphere
On 22 December (winter solstice) the Sun's vertical rays are at the Tropic of Capricorn (23.5 S). The Northern Hemisphere is then tilted away from the Sun, so it has its shortest day and longest night. 21 March and 23 September are equinoxes (equal day and night); 22 November is not a special date. (NCERT Class 6, Motions of the Earth; NCERT Class 11 Fundamentals ch. 2 / Goh Cheng Leong ch. 1.)
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