Question

An atom absorbs or emits only parricular frequencies of light. White light bends into a glass prism and separates into a rainbow of colors. In which of these two scenarios does the electromagnetic radiation behave as a wave? As a particle?

Short answer

Light behaves as a wave in a prism and as particles during atomic energy changes.

Step-by-step solution

Understanding Electromagnetic Radiation

Electromagnetic radiation exhibits both wave-like and particle-like properties. Depending on the scenario, it can behave either as a wave or as a particle due to its dual nature.

Analyzing the Scenarios

The two scenarios given are: first, an atom absorbing or emitting particular frequencies of light, and second, white light bending in a glass prism and separating into a rainbow of colors.

Wave-like Behavior: Refraction in a Prism

When white light enters a glass prism, it bends and splits into different colors, forming a spectrum. This process is due to refraction, a characteristic of wave behavior where light waves change speed and direction when passing through a medium. So, in this scenario, electromagnetic radiation behaves as a wave.

Particle-like Behavior: Atomic Absorption and Emission

In the scenario where an atom absorbs or emits specific frequencies of light, electromagnetic radiation behaves as particles, known as photons. This is because only particular energy levels (quantum states) are involved, showing the quantized nature of light's interaction with matter.

Key concepts

Wave-Particle Duality

Wave-particle duality is a fundamental concept in physics that describes how electromagnetic radiation, such as light, exhibits both wave-like and particle-like properties. This dual nature helps explain various phenomena that cannot be understood if light were only a wave or only a particle. For instance, the behavior of light as a wave can be observed through interference patterns and diffraction, where light spreads out and overlaps to create distinctive patterns.
On the other hand, when light behaves as particles, known as photons, it can explain phenomena like the photoelectric effect, where light impacts a material and releases electrons. This particle nature is also observed in atomic absorption and emission, where light is absorbed or emitted in discrete packets or quanta. Understanding this duality allows scientists to predict and explain a wide range of behaviors in different scenarios.

Light Absorption and Emission

Light absorption and emission are phenomena closely tied to the particle nature of light. In an atom, these processes occur at specific frequencies, correlating to particular energy levels or quantum states. This is because atoms can absorb or emit electromagnetic radiation only when photons have the right amount of energy to match the difference between these energy levels.

• Light Absorption: Occurs when an atom takes in a photon, moving an electron to a higher energy state.
• Light Emission: Occurs when an electron falls back to a lower energy state, releasing a photon.

This characteristic is essential for understanding how lasers work or why certain materials appear to be a particular color. The specificity of these energy levels reveals the quantized nature of atomic interactions, a clear indicator of light's particle behavior.

Refraction in a Prism

Refraction is the bending of light as it passes through different media, and it's a perfect illustration of light's wave nature. When white light enters a prism, it slows down and bends due to the change in medium from air to glass. Each color in the light spectrum bends at different angles, leading to the dispersion of white light into a rainbow.

• Refraction: Change in the speed of light when passing through different media.
• Dispersion: Separation of white light into a spectrum of colors.

This process highlights light's ability to exhibit wave-like characteristics. The angle and degree of bending depend on the wavelength of the light, as longer wavelengths (red) bend less than shorter wavelengths (blue). Refraction not only underpins the operation of lenses and optics but also helps us understand atmospheric phenomena such as rainbows.