Geography: Introduction – NDA Geography PYQs

NDA 2024-II

Q. 1. Eratosthenes, a Greek philosopher, measured the Earth’s circumference based on the angle of Sun rays at two different points. Which cities were they?

(a) Alexandria and Syene

(b) Syene and Troy

(c) Alexandria and Troy

(d) Alexandria and Thebes

Answer: (a) Alexandria and Syene

Explanation: Eratosthenes used two Egyptian cities for his famous measurement: Syene (modern-day Aswan): where the sun shone directly overhead (no shadow) at noon on the summer solstice, showing it was on the Tropic of Cancer. Alexandria: located north of Syene, where the sun cast a shadow at approximately 7.2° (one-fiftieth of a full circle = 360°) from vertical at the same moment. By knowing the angle difference (7.2°) and the distance between the cities (~800 km), he calculated the full circumference: 800 km × (360°/7.2°) = 40,000 km. Troy and Thebes are not associated with this measurement. Concept Tested: Eratosthenes used Alexandria and Syene (Aswan) to calculate Earth’s circumference: using shadow angle and distance

NDA 2019-II

Q. 2. Which Greek philosopher coined the term “Geography” in the 3rd century BCE?

(a) Pythagoras

(b) Plato

(c) Eratosthenes

(d) Clio

Answer: (c) Eratosthenes

Explanation: Eratosthenes coined the word “Geography” (from Greek: Geo = Earth, Graphia = description/writing) in the 3rd century BCE. His major work “Geographica” (now lost) was among the first systematic attempts to describe the world. Pythagoras was known for mathematics (Pythagorean theorem) and believed the Earth was spherical. Plato was a philosopher. Clio is the Greek Muse of History: not a geographer. Concept Tested: Eratosthenes coined the term “Geography” (geo = Earth, graphia = description) in the 3rd century BCE

NDA 2008-II

Q. 3. Who among the following was first to measure the circumference of the Earth?

(a) Eratosthenes

(b) Aristotle

(c) Hecataeus

(d) Herodotus

Answer: (a) Eratosthenes

Explanation: Eratosthenes of Cyrene (c. 276–194 BCE) was a Greek polymath who became the first person to measure the circumference of the Earth with reasonable accuracy. He observed that at noon on the summer solstice, the sun shone directly overhead at Syene (present-day Aswan, Egypt): there was no shadow. At the same time, in Alexandria (north of Syene), the sun cast a shadow at an angle of about 7.2° from vertical. Knowing the distance between the two cities, he calculated the Earth’s circumference as approximately 40,000 km. His estimate is remarkably close to the actual circumference (~40,075 km). Aristotle showed Earth was spherical but did not measure it. Hecataeus and Herodotus were ancient geographers and historians, not associated with Earth’s measurement. Concept Tested: Eratosthenes: first scientist to measure Earth’s circumference using sun angle and distance between cities

★ JOVIK Exam Insight Eratosthenes is one of the most important names in NDA Geography Introduction questions. He appears in NDA 2008-II, 2019-II, and 2024-II. Remember three things about him: 1. First to measure the circumference of the Earth. 2. Used cities: Alexandria and Syene (Aswan). 3. Coined the term “Geography” (from Greek: Geo = Earth, Graphia = description).

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