Question

The temperature of the center of the earth is about
(A) $ 4000^\circ C $
(B) $ 6000^\circ C $
(C) $ {10^4}^\circ C $
(D) $ {10^6}^\circ C $

Answer 1

Hint
We will discuss how the temperature of the center of the earth is calculated by experiment and why the earth core is so hot. Based on this we will get the answer as it is the fact-based question.

Complete step by step answer
There are three main sources of heat in deep earth i.e. core, mantle.
(1) heat from the time of planet formation which has not been lost.
(2) frictional heating resulting by denser material sinking to the centre of the planet
(3) Heat resulted by decay of radioactive elements.
The earth’s core consists mainly of a sphere of the liquid iron at temperature above $ 4000^\circ C $ and pressure of more than 1.3 million atmospheres. The temperature difference between the earth’s core and mantle is the main reason for the large-scale thermal movements.
Scientists will look at the melting point of iron at various pressures in the laboratory to produce an accurate image of the temperature profile within the Earth's core, using a diamond anvil cell process to compress samples to pressures of several million atmospheres, and powerful laser beams to heat them to 4000 or even 5000 degrees Celsius.
Scientists have determined the temperature of the earth center to be $ 6000^\circ C $ , $ 1000^\circ C $ hotter than in the previous experiment 20 years ago.
Option(B); $ 6000^\circ C $ is the correct option.

Note
Do not confuse the iron melting point $ 4000^\circ C $ as the answer because there are various things in earth’s core which contribute to its temperature although iron has the major share in it. Although $ 6000^\circ C $ is not an accurate value but temperature is around this only, which is calculated by experiment.