Difficulty: Easy
Correct Answer: Inner core at the centre of the Earth
Explanation:
Introduction / Context:
Pressure is a measure of force acting per unit area, and it increases when more material is pressing down from above. In both the atmosphere and inside the Earth, pressure changes with depth or altitude. The atmosphere has layers such as the troposphere, stratosphere and ionosphere, while the Earth interior has layers such as crust, mantle, outer core and inner core. This question asks you to compare the listed layers and identify where the pressure is highest.
Given Data / Assumptions:
Concept / Approach:
In the atmosphere, air pressure is highest at sea level and decreases as altitude increases, because there is less air above you. Thus, among atmospheric layers, the troposphere has higher pressure than the stratosphere and ionosphere. Inside the Earth, moving downward from the crust through the mantle and core, the amount of overlying material increases enormously, leading to extremely high pressures. At the Earth centre, in the inner core, pressures reach millions of times atmospheric pressure. When comparing the atmosphere layers with the inner core, the inner core has far greater pressure than any atmospheric region, so it is the correct choice.
Step-by-Step Solution:
Step 1: Recall that atmospheric pressure decreases with altitude, so the ionosphere, which is very high, has very low pressure.Step 2: Recognise that the stratosphere lies above the troposphere, so pressure in the stratosphere is lower than in the troposphere.Step 3: Note that the troposphere is the lowest atmospheric layer and has the highest pressure among atmospheric layers.Step 4: Consider the Earth interior: as depth increases, more rock and metal lie above, increasing the pressure.Step 5: Understand that the inner core is the deepest layer, at the centre of the Earth, and therefore experiences the maximum pressure.Step 6: Compare the maximum atmospheric pressure with the enormous pressures in the inner core and see that the inner core pressure is much higher.Step 7: Conclude that among the listed layers, the inner core has the highest pressure.
Verification / Alternative check:
Scientific estimates suggest that pressure at the centre of the Earth is on the order of several million atmospheres. In contrast, atmospheric pressure at sea level is defined as 1 atmosphere, and even at the bottom of the troposphere or within weather systems, it only varies by a few percent around this value. High in the ionosphere, the air is so thin that pressure is only a tiny fraction of surface pressure. These orders of magnitude show that the inner core has vastly higher pressure than any atmospheric layer, confirming it as the correct answer.
Why Other Options Are Wrong:
The ionosphere is far above the Earth surface and has very low pressure due to the extremely thin air. The stratosphere is also higher than the troposphere, so its pressure is lower than at lower altitudes. The troposphere has higher pressure than the layers above it, but its pressure is still tiny compared with the colossal pressures inside the Earth core. Thus none of the atmospheric layers listed can compete with the inner core for maximum pressure.
Common Pitfalls:
Some learners may read only atmospheric layers and quickly choose the troposphere, forgetting that the inner core is an Earth interior layer included in the options. Others may think that ionosphere sounds intense and therefore must have high pressure, but higher altitude always means lower pressure in the atmosphere. To avoid such mistakes, carefully read all options and remember that pressure increases with depth inside the Earth and decreases with height in the atmosphere.
Final Answer:
The pressure is highest in the inner core at the centre of the Earth.
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