Which of the following layer of interior of earth is in liquid state?

Question

Accepted Answer

The correct option is 2:

The Outer Core is the correct answer because it is the only major layer within the Earth's interior that is confirmed to be in a liquid state. This layer, which extends from approximately 2,900 km to 5,150 km below the Earth's surface, is primarily composed of iron and nickel. The extremely high temperatures (up to 6,100 °C) in the outer core, combined with the lower pressures relative to the inner core, prevent these metals from solidifying. The movement of this hot, molten iron is critical as it generates electric currents, which, in turn, produce the Earth's magnetic field (geodynamo). Seismic studies, particularly the fact that S-waves (shear waves) cannot travel through this layer, definitively prove its liquid nature.

The incorrect option is 1 (Mental):
The term "Mental" appears to be a misspelling of "Mantle." The mantle is the layer beneath the crust and above the core. While the upper part of the mantle (asthenosphere) exhibits plastic, flowing behavior over geological timescales, the bulk of the mantle is considered to be in a solid state, even though it is extremely hot. Therefore, it is not a liquid layer like the outer core.

The incorrect option is 3 (Inner core):
The Inner Core is situated at the very center of the Earth and is in a solid state. Although temperatures here are even hotter than in the outer core, the immense pressure (reaching millions of atmospheres) at this depth compresses the iron and nickel atoms so tightly that they cannot melt, keeping the inner core solid despite the heat.

The incorrect option is 4 (Crust):
The Crust is the outermost and thinnest layer of the Earth, consisting of rigid, solid rock. It is divided into continental and oceanic crusts. The crust is entirely in a solid state and is the cool, brittle surface upon which we live. Geological processes involve fracturing and shifting of this solid rock, not its conversion into a liquid state.