Many scientists have performed experiments to explore the interaction of light and matter. Analyse how evidence from at least THREE such experiments has contributed to our understanding of physics. (8 marks) --- 16 WORK AREA LINES (style=lined) --- Students could include any of the following experiments: Young’s Double-Slit Experiment: → Young’s 1801 double slit experiment aimed to determine light’s wave-particle nature. → He passed coherent light through two slits and observed the pattern on a screen. → Instead of Newton’s predicted two bright bands, Young observed alternating bright and dark bands. → This interference pattern occurred due to light diffraction and interference, which re wave properties. → The experiment provided strong evidence for light behaving as a wave at macroscopic scales. Planck and the Blackbody Radiation Crisis: → Late 19th century scientists studied the relationship between black body radiation’s wavelength and intensity. → Experimental observations showed intensity peaked at a specific wavelength, contradicting classical physics predictions. → Classical physics led to the “ultraviolet catastrophe,” which violated energy conservation. → Planck’s thought experiment resolved this by proposing energy was transferred in discrete packets (quanta) where \(E=hf\). → This revolutionary idea marked a shift from classical physics to quantum theory. Einstein and the Photoelectric Effect: → In 1905, Einstein built upon Plank’s idea of quantised energy to propose that light was made up of quantised photons where \(E=hf\). → Einstein proposition explained why electrons are ejected from metal surfaces only when light exceeds a minimum frequency. → Previous to Einstein’s explanation of the photoelectric effect a high intensity of light corresponds to a high energy. → Einstein proposed that the KE of the emitted electrons was proportion to the frequency of the light rather than the intensity of the light. → This development in the understanding of the interaction of light and matter at the atomic level shifted our understanding of light to a wave-particle duality model. Cosmic Ray Experiments and the development of the Standard Model: → In 1912, Victor Hess discovered cosmic rays through high-altitude balloon experiments, finding that radiation increased with altitude rather than decreased as expected. → The study of cosmic rays led to the unexpected discovery of new particles, including the positron and muon, which couldn’t be explained by the known models of matter. → These discoveries from cosmic rays helped inspire the development of modern particle accelerators and contributed to the formulation of the quark model in the 1960s. → Eventually further studies on these newly discovered particles led to the development of the Standard Model of particle physics, which organises all known elementary particles and their interactions. Students could include any of the following experiments: Young’s Double-Slit Experiment: → Young’s 1801 double slit experiment aimed to determine light’s wave-particle nature. → He passed coherent light through two slits and observed the pattern on a screen. → Instead of Newton’s predicted two bright bands, Young observed alternating bright and dark bands. → This interference pattern occurred due to light diffraction and interference, which re wave properties. → The experiment provided strong evidence for light behaving as a wave at macroscopic scales. Planck and the Blackbody Radiation Crisis: → Late 19th century scientists studied the relationship between black body radiation’s wavelength and intensity. → Experimental observations showed intensity peaked at a specific wavelength, contradicting classical physics predictions. → Classical physics led to the “ultraviolet catastrophe,” which violated energy conservation. → Planck’s thought experiment resolved this by proposing energy was transferred in discrete packets (quanta) where \(E=hf\). → This revolutionary idea marked a shift from classical physics to quantum theory. Einstein and the Photoelectric Effect: → In 1905, Einstein built upon Plank’s idea of quantised energy to propose that light was made up of quantised photons where \(E=hf\). → Einstein proposition explained why electrons are ejected from metal surfaces only when light exceeds a minimum frequency. → Previous to Einstein’s explanation of the photoelectric effect a high intensity of light corresponds to a high energy. → Einstein proposed that the KE of the emitted electrons was proportion to the frequency of the light rather than the intensity of the light. → This development in the understanding of the interaction of light and matter at the atomic level shifted our understanding of light to a wave-particle duality model. Cosmic Ray Experiments and the development of the Standard Model: → In 1912, Victor Hess discovered cosmic rays through high-altitude balloon experiments, finding that radiation increased with altitude rather than decreased as expected. → The study of cosmic rays led to the unexpected discovery of new particles, including the positron and muon, which couldn’t be explained by the known models of matter. → These discoveries from cosmic rays helped inspire the development of modern particle accelerators and contributed to the formulation of the quark model in the 1960s. → Eventually further studies on these newly discovered particles led to the development of the Standard Model of particle physics, which organises all known elementary particles and their interactions.
PHYSICS, M7 2024 HSC 32
Many scientists have performed experiments to explore the interaction of light and matter. Analyse how evidence from at least THREE such experiments has contributed to our understanding of physics. (8 marks) --- 16 WORK AREA LINES (style=lined) ---