CSS - PMS - CCE - PCS - Geography
Earth's Shape and Structure
A reference ellipsoid is used because it:
A. Exactly reproduces every mountain and trench
B. Provides a smooth mathematical approximation of Earth's shape
C. Represents only the atmosphere
D. Shows only ocean depth
Correct Answer: B
A reference ellipsoid is a smooth mathematical surface used for mapping and geodetic calculations.
CSS - PMS - CCE - PCS - Geography
Earth's Shape and Structure
The Earth's flattening is approximately:
A. 1/30
B. 1/100
C. 1/298
D. 1/1000
Correct Answer: C
Earth's geometric flattening is about 1/298.257.
CSS - PMS - CCE - PCS - Geography
Earth's Shape and Structure
Gravity is generally slightly stronger at the poles than at the equator because:
A. The poles are hotter
B. The poles are closer to the Earth's center and centrifugal effect is smaller
C. The equator has more mountains
D. The poles have thicker atmosphere
Correct Answer: B
Polar flattening places the poles slightly closer to Earth's center, and centrifugal force is least at the poles.
CSS - PMS - CCE - PCS - Geography
Earth's Shape and Structure
The science concerned with measuring the Earth's size and shape is called:
A. Petrology
B. Geodesy
C. Meteorology
D. Paleontology
Correct Answer: B
Geodesy deals with the measurement and representation of the Earth, including its size, shape and gravity field.
CSS - PMS - CCE - PCS - Geography
Earth's Shape and Structure
The approximate equatorial circumference of the Earth is:
A. 30,075 km
B. 35,075 km
C. 40,075 km
D. 45,075 km
Correct Answer: C
The equatorial circumference is approximately 40,075 km.
CSS - PMS - CCE - PCS - Geography
Earth's Shape and Structure
The Earth's equatorial diameter is approximately how much greater than its polar diameter?
A. About 12 km
B. About 22 km
C. About 42 km
D. About 82 km
Correct Answer: C
The equatorial diameter exceeds the polar diameter by roughly 42 km.
CSS - PMS - CCE - PCS - Geography
Earth's Shape and Structure
The approximate polar diameter of the Earth is:
A. 10,714 km
B. 11,714 km
C. 12,714 km
D. 13,714 km
Correct Answer: C
The polar diameter is about 12,714 km.
CSS - PMS - CCE - PCS - Geography
Earth's Shape and Structure
The approximate equatorial diameter of the Earth is:
A. 10,756 km
B. 11,756 km
C. 12,756 km
D. 13,756 km
Correct Answer: C
The equatorial diameter is about 12,756 km, slightly larger than the polar diameter.
CSS - PMS - CCE - PCS - Geography
Earth's Shape and Structure
The approximate mean radius of the Earth is:
A. 3,371 km
B. 5,371 km
C. 6,371 km
D. 8,371 km
Correct Answer: C
The Earth's mean radius is about 6,371 km.
CSS - PMS - CCE - PCS - Geography
Earth's Shape and Structure
The Earth is slightly flattened at the:
A. Equator
B. Poles
C. Tropics
D. Prime Meridian
Correct Answer: B
Earth's rotation causes polar flattening and an equatorial bulge.
CSS - PMS - CCE - PCS - Geography
Earth's Shape and Structure
The Earth's equatorial bulge is mainly caused by:
A. Solar radiation
B. Earth's rotation
C. Tidal friction
D. Plate tectonics
Correct Answer: B
Rotation produces centrifugal force, which is greatest at the equator and causes the equatorial bulge.
CSS - PMS - CCE - PCS - Geography
Earth's Shape and Structure
The term 'geoid' refers to:
A. A perfect mathematical sphere
B. The Earth's irregular gravity-defined shape
C. Only the ocean floor
D. The Earth's magnetic field
Correct Answer: B
A geoid is the gravity-defined, irregular equipotential surface that approximates mean sea level.
CSS - PMS - CCE - PCS - Geography
Earth's Shape and Structure
The actual shape of the Earth is best described as:
A. Perfect sphere
B. Oblate spheroid
C. Prolate spheroid
D. Flat disc
Correct Answer: B
Earth is slightly flattened at the poles and bulged at the equator, so its shape is an oblate spheroid.