Flashcard: Quantum 101

Front

What is a fundamental characteristic that distinguishes quantum mechanics from classical physics at the smallest scales?

Back

Energy, momentum, and other quantities are quantized.

Answer explanation

A fundamental characteristic of quantum mechanics is that energy, momentum, and other quantities are quantized, meaning they can only take on discrete values, unlike in classical physics where they are continuous.

Front

The idea that energy can only exist in discrete packets is attributed to:

Back

Max Planck

Answer explanation

The concept of energy existing in discrete packets, known as quanta, was introduced by Max Planck in 1900. This foundational idea led to the development of quantum theory, distinguishing Planck as the key figure in this area.

Front

What term describes the smallest indivisible unit of energy?

Back

Quantum

Answer explanation

The term 'quantum' refers to the smallest indivisible unit of energy, representing discrete packets of energy in quantum mechanics. While photons are energy carriers, 'quantum' is the broader term for energy units.

Front

Light, in the quantum mechanical view, exhibits properties of both:

Back

Particles and probability waves

Answer explanation

Light exhibits both particle-like properties, as seen in photons, and wave-like properties, described by probability waves in quantum mechanics. Thus, the correct answer is 'Particles and probability waves'.

Front

The famous double-slit experiment demonstrates which fundamental concept of quantum mechanics?

Back

Wave-particle duality

Answer explanation

The double-slit experiment illustrates wave-particle duality by showing that particles like electrons can exhibit both wave-like and particle-like behavior, depending on whether they are observed.

Front

In the double-slit experiment with electrons, even when sent one at a time, they still create an interference pattern. This suggests that:

Back

Electrons can be in multiple places at once.

Answer explanation

The interference pattern indicates that electrons exhibit wave-like behavior, allowing them to be in multiple places at once, which is a fundamental principle of quantum mechanics.

Front

What does measuring a quantum system generally cause it to do?

Back

Collapse into a definite state

Answer explanation

Measuring a quantum system causes it to collapse into a definite state due to the observer effect, which forces the system to choose a specific outcome from its possible states.

Front

Heisenberg's uncertainty principle states that there is a fundamental limit to the precision with which we can simultaneously know certain pairs of physical properties of a particle, such as:

Back

Position and momentum

Answer explanation

Heisenberg's uncertainty principle specifically addresses the limits of measuring position and momentum simultaneously. This means that the more accurately we know one, the less accurately we can know the other.

Front

Quantum probability waves are described by a mathematical function called the:

Back

Wavefunction

Answer explanation

Quantum probability waves are represented by the wavefunction, which encodes the probabilities of finding a particle in various states. The wavefunction is fundamental in quantum mechanics, unlike the other options listed.

Front

The square of the amplitude of the wavefunction at a given point in space tells us:

Back

The probability of finding the particle at that point.

Answer explanation

The square of the amplitude of the wavefunction at a given point represents the probability density of finding the particle at that point in space, making 'the probability of finding the particle at that point' the correct choice.