Question

What is the polar radius of the earth?
A) 6000 km
B) 6357 km
C) 6400 km
D) 6350 km

Answer 1

Hint: Earth radius depends on how it's measured either from equator or polar. The equatorial radius of earth is over its polar radius that is 6378 km. The earth’s polar radius is the distance from its center to the North and South Poles.

Complete answer:
The polar radius is the distance from the middle to the surface along that axis. The polar radius of the planet is 6357 km and also the polar diameter is 12,714 km.
The equatorial diameter of earth is about 12,756 km. The equatorial bulge is because of the force extended on the earth by its rotation. We often describe it as a sphere but it's more like an oblate spheroid.

Now let us look into the given options
A) 6000 km is the wrong answer because it won't create an oblate spheroid.Hence Option A is incorrect.
B) 6357 km is the correct answer because it would create an oblate spheroid. Hence Option B is the correct answer.
C) 6400 km is the wrong answer because it won't create an oblate spheroid.Hence Option C is an incorrect answer.
D) 6350 km is the wrong answer because it won't create an oblate spheroid.Hence Option D is incorrect.

Hence the correct answer is option ‘B’.

Note: Those involved within the study of measuring the planet, called geodesists. The polar regions are the foremost inhospitable places on the earth. External tidal forces and earth’s rotation causes its shape to deviate from a perfect sphere.