Se necesitan enormes cantidades de fotones de microondas...

Se necesitan enormes cantidades de fotones de microondas para calentar una muestra macroscópica de materia. Una ración de sopa que contiene $252 \mathrm{~g}$ de agua se calienta en un horno de microondas de 20 a $98^{\circ} \mathrm{C}$, con radiación de longitud de onda de $1.55 \times 10^{-2} \mathrm{~m}$. ¿Cuántos fotones son absorbidos por el agua en la sopa?

Key Concepts

Energy of a Photon

This concept explains that electromagnetic radiation is quantized, meaning light comes in discrete packets called photons. The energy of one photon is determined by the relation E = hc/?, where h is Planck's constant, c is the speed of light, and ? is the wavelength. This relationship is fundamental in quantum physics for understanding interactions between radiation and matter.

Planck's Constant and the Speed of Light

Planck's constant (h) and the speed of light (c) are critical constants in quantum mechanics and electromagnetism. Planck's constant sets the scale for quantum effects and defines the size of energy quanta, while the speed of light is a universal constant that appears in many equations, including the one for photon energy. Their product with the inverse of the wavelength gives the energy of a photon.

Specific Heat Capacity and Thermal Energy Calculation

Specific heat capacity is a property of a substance that indicates the amount of heat required to raise the temperature of a unit mass by one degree Celsius. In thermal physics, the total energy needed to change the temperature of a quantity of matter is calculated by the formula Q = mc?T, where m is the mass, c is the specific heat capacity, and ?T is the temperature change. This calculation provides the macroscopic energy input associated with a temperature change.

Photon Count Calculation

Once the energy of a single photon and the total energy required to heat the substance are known, the total number of photons absorbed can be determined by dividing the total energy by the energy per photon. This step bridges macroscopic thermodynamics with microscopic quantum phenomena, illustrating how many quantum events (photon absorptions) are needed to result in a measurable change in temperature.

Transcript

Please give Ace some feedback