In introductory texts, some "special" rays are selected to draw the image produced by lenses and mirrors. After teaching special rays, students usually ask how to draw an arbitrary ray. One method for drawing an arbitrary ray is the "tilted principal axis." As an example, the tracing of an arbitrary ray in diverging lens is…

This article is about a famous physics course taken by thousands of students at Amherst College in the 1950s, designed and taught by its distinguished instructor, Arnold B. Arons. There are very few of us left who have taken the course. The youngest one would be, as the course was discontinued in 1968, about 72 years old!

The refractive index (RI) is probably the single most important parameter in optical systems. Chromatic dispersion, on the other hand, indicates how the RI depends on the wavelength and is central in, e.g., optical communication systems. Chromatic dispersion also plays an important role when teaching optics due to the captivating natural…

In this paper, we utilize the readily known theory of the ideal transformer to furnish a self-contained qualitative explanation on the AC-powered Thomson jumping ring (TJR) experiment.

In conventional physics teaching, acceleration measurement is demonstrated using motion sensors and carts on inclined tracks, and relevant data are collected using specific professional software. This approach entails the connection of computers and interface boxes, and requires high cost and large space. Air-track carts can be used to perform…

Of all the conceivable ideal-gas processes, almost all introductory physics textbooks as well as more advanced texts on thermodynamics emphasize only four: isochoric, isobaric, isothermal, and adiabatic (isentropic). These are processes in which a state variable--volume, pressure, temperature, or entropy--remains constant. It turns out that these…

The wave nature of light has been widely demonstrated in a double-slit experiment, which has played a special role in physics teaching. When monochromatic light passes through the double-slit sheet, the diffraction and interference fringes can be observed in the far-field regime. The interference of light causes the beams passing through the two…

It is difficult for an instructor to just make up valid numbers for B[subscript x], B[subscript y], B[subscript z], E[subscript x], E[subscript y], and E[subscript z] in the creation of homework problems and test questions calculating the Poynting vector. In this paper, 25 examples are given of the electric and magnetic fields of electromagnetic…

This paper shares findings from a teacher designed physics and computing unit that engaged students in learning physics and computing concurrently thru inquiry. Using scientific inquiry skills and practices, students were tasked with assessing the validity of local rollercoaster g-force ratings as posted to the public. Students used computational…

In this work, we study several closely related problems involving chains, conveyor belts, and rockets, which are described and solved without the application of infinitesimal calculus, or even the concept of mathematical limit. On one hand, the novelty lies not in the problems themselves, but in the method used for their solution, which brings…

In this paper, an experimental setup composed of a color-mixing device, power supply, and spectrometer is developed. This setup is available for students to do hands-on color mixing with red, green, and blue light in undergraduate labs. LED volt-ampere and spectrum characteristics are investigated. The apparatus was used to perform additive color…

Measurements and calculations are presented showing how the trajectory of an object sliding across an inclined plane varies with the launch and incline angles. The trajectory depends on the magnitude and direction of the sliding friction force. The experiment is easy to set up, can be analysed using a video camera, and would be suitable for a…

The photoelectric effect consists of electrons emerging from the region near the inner surface of a metallic solid toward the outside vacuum, when the metal surface is illuminated. The effect depends on the frequency of the light waves and the properties of the metal surface. In particular, a minimum or "threshold" frequency of light is…

In an earlier article I argued that much of what used to be called "modern physics" stems from the intersection of two earlier technologies: high vacuum and high voltage. In this article I will discuss the induction coil, invented in the 1830s, reinvented in the second half of the 19th century, and still used today to produce the high…

Nearly everyone, including physics students, finds rainbows to be fascinating and much has been written about them. For example, in a 2020 paper, Kenneth Ford sets forth the basic theory of rainbows created by water droplets at the level of geometric optics and uses a graphical approach to address the question of the relative intensities of the…