Module 6

1. Module 6

1.5. Page 3

Lesson 1

Module 6—Wave-Particle Duality and Quantum Physics

Reflect and Connect

A photograph shows the glowing coils of three stove elements, with the focus on the centre element. Its yellow and red colours indicate that the temperature is greater near the centre and coolest on the outside of the coil.

Blackbody radiation curves can be explained using quantum theory. Consider the stove element. When you turn on the stove, the element absorbs electrical energy and begins to heat up. When the temperature of the stove element exceeds that of the surroundings, it releases energy with photons in the infrared range of wavelength and frequency. Each photon transfers a specific amount of energy. As the element’s temperature continues to rise, more energy is radiated. This can be achieved by emitting more photons in the infrared wavelength, each removing a quantum of energy or by emitting photons with a greater frequency (visible light) such that each photon transfers a larger quantum of energy. According to the radiation curves, both strategies apply. At greater temperatures the curve moves upward on the intensity scale, meaning more photons are released. At high temperatures, the curve also moves laterally to higher frequency (smaller wavelength) radiation, adding more photons that transfer higher individual quanta of energy. This explains why the stove element begins to glow red as it continues to heat up. At peak temperature it will release most of the energy in infrared photons and the remaining energy in visible light photons.

In the photo on the right, the yellow-to-red colouring in the coil indicates that the temperature is greater near the centre and coolest on the outside. This simple observation and the quantum theory that explains it represent a shift from classical physics to quantum physics.

Module 6: Lesson 1 Assignment

Remember to submit the Module 6: Lesson 1 Assignment to your teacher.