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In the lungs there are tiny sacs of air, which are called alveoli. An oxygen molecule (mass \(=5.3 \times 10^{-26} \mathrm{kg}\) ) is trapped within a sac, and the uncertainty in its position is \(0.12 \mathrm{mm} .\) What is the minimum uncertainty in the speed of this oxygen molecule?

Short Answer

Expert verified
The minimum uncertainty in speed is approximately 10 m/s.

Step by step solution

01

Understanding the Uncertainty Principle

The uncertainty principle states that the uncertainty in position \(\Delta x\) and the uncertainty in momentum \(\Delta p\) (or speed \(\Delta v\)) of a particle are related by the equation \[\Delta x \cdot \Delta p \geq \frac{\hbar}{2}.\] Here, \(\hbar\)\"],\

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Uncertainty in Position
The concept of uncertainty in position provides a fundamental insight into the unpredictable nature of particle locations. In quantum mechanics, a particle like an oxygen molecule trapped in a small air sac called an alveolus has a position that can't be precisely determined. Instead of pinpointing the exact location, we talk about the uncertainty, denoted by \(\Delta x\). This means we know the region or range where the particle might be.
For a practical example, the uncertainty in the position for an oxygen molecule can be as small as a few hundredths of a millimeter. This small uncertainty in position is critical because it directly influences other uncertainties, like momentum. In the given problem, this uncertainty is given as 0.12 mm. The understanding of \(\Delta x\) is essential to apply the famous Heisenberg Uncertainty Principle to find related uncertainties like momentum or speed.
Uncertainty in Momentum
Uncertainty in momentum is directly connected to the uncertainty in position by Heisenberg's Uncertainty Principle. Momentum, symbolized by \(p=m imes v\) where \(m\) is mass and \(v\) is velocity, reflects the motion's uncertainty. In this principle, we use \(\Delta p\), which describes the inability to precisely measure the momentum of a particle when its position is mostly known.
To calculate momentum uncertainty, we use the equation \(\Delta x \cdot \Delta p \geq \frac{\hbar}{2}\), where \(\hbar\) is the reduced Planck's constant. This inequality tells us there's a trade-off: better precision in position leads to more uncertainty in momentum.
In practical terms, if we take the given position uncertainty of an oxygen molecule as 0.12 mm, the Heisenberg Uncertainty Principle helps us compute the smallest possible uncertainty in the molecule's speed. This approach not only informs how much its speed can vary but also illustrates the fundamental limits of measurement at the quantum scale.
Quantum Mechanics
Quantum mechanics is the branch of physics that peeks into the microscopic universe, where the rules differ from our everyday experiences. It governs the behavior of tiny particles, like electrons and molecules, through principles like the Heisenberg Uncertainty Principle.
This principle is a core aspect of quantum mechanics, emphasizing the inherent limitations in measuring pairs of complementary properties, like position (\(x\)) and momentum (\(p\)).
  • At the quantum level, particles exhibit wave-like behavior, making it impossible to ascertain both position and momentum precisely.
  • This duality challenges and enriches our understanding, illustrating how particles like oxygen molecules in alveoli can only be described in terms of probabilities.
  • The uncertainty in measurements is not a flaw but a fundamental trait of nature, transforming our approach to physical laws and experiments.
Ultimately, quantum mechanics compels us to think beyond classical physics, embracing a probabilistic framework to explain the very fabric of what exists at the most fundamental levels.

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