KORAKU vs Charged Physics Lab

KORAKU is an interactive educational app that visualizes how light behaves in real time. Bend rays with lenses and mirrors, overlap light as a wave, and explore color and photons to connect the equations with what you see. Developer: Fuji Bit Inc. KORAKU is the optics edition of the "-raku" physics simulation series. It turns the optics of school and university physics into moving pictures, not just formulas. 12 simulations in 3 categories: - Rays & Images - Lens: Trace rays through convex and concave lenses. Change the focal length, object distance and height to see the image switch between real and virtual, inverted and upright. Explore 1/f = 1/a + 1/b. - Mirror: Switch between concave and convex mirrors. Move the radius R and object distance a to see how the image changes around the focal point F and center of curvature C, and why a virtual image appears behind the mirror. - Eye & Glasses (new): See the cornea and lens focus an image on the retina. Choose a normal, nearsighted or farsighted eye and change the viewing distance, glasses power (diopters) and accommodation to see where the image forms and how blurry it looks. One tap sets matching glasses. - Prism: Watch white light split into a spectrum. Change the apex angle, angle of incidence and refractive index to see dispersion bend each color differently, with the deviation and minimum deviation. - Optical fiber: See light travel by total internal reflection. Change the launch angle and refractive indices to explore the critical angle, numerical aperture (NA) and when light leaks into the cladding. - Light as a Wave - Diffraction grating: Change the number of slits, spacing and wavelength to find the bright lines at d sin(theta) = m lambda, and watch them sharpen as slits are added. - Thin film: Recreate the colors of soap bubbles and oil films. Change the thickness, refractive index and angle to shift the bright and dark wavelengths. - Polarization: Rotate a polarizer and an analyzer to see Malus's law, I = I0 cos^2(theta): brightest at 0 and 180 degrees, blocked at 90. - Color & the Nature of Light - Color mixing: Compare additive mixing of light (RGB) with subtractive mixing of paint (CMY) using three sliders. - Rainbow: Follow sunlight as it refracts into a raindrop, reflects inside and refracts out. See why the primary bow appears about 42 degrees from the antisolar point, the secondary about 51 degrees, with the colors reversed. - Blue Sky & Sunset (new): See sunlight scattered in the atmosphere. Switch between Rayleigh scattering (proportional to 1/lambda^4) and Mie scattering (cloud droplets, haze), and change the sun altitude and air density. As the air mass grows, the sky and sun turn from daytime blue to sunset colors. - Photoelectric effect: Shine light on a metal and watch electrons fly out. Change the frequency, intensity and work function to explore E = hf, Kmax = hf - W and the threshold frequency f0, with the visible and UV bands marked. Features: - Clean, modern design (dark and light themes) - Home screen organized by category - Tips and a play button in the control panel - Parameter sliders with results that update in real time - Legends and labels for every symbol and colored ray on screen - An explanation sheet with formulas for every simulation - In landscape, the canvas and control panel are shown side by side - Supports larger text sizes - VoiceOver reads out each screen's result (real or virtual image, total internal reflection, and more) - 73 languages including English and Japanese, following your device language - No sign-in: start exploring right away Price: - Free - In-app purchases: none - Subscriptions: none - Ads: a banner ad by Pangle at the bottom of the screen The "-raku" educational app series: - SUUGAKU - Mathematics - BUTURAKU - Mechanics - DENRAKU - Electromagnetism - HARAKU - Waves - KORAKU - Optics

Charged Physics Lab turns the Physics I and Physics II formula sheet into an interactive problem-solving workspace. Start with the language in a homework problem, a quantity you need, or a formula you recognize. Search across 200 equations or browse the Formula Map by physics section. Open a formula to see its variables, fixed units, physical meaning, and a diagram that responds to the values in the equation. The equation itself is the calculator. Tap a variable tile to enter a value. Hold a tile to isolate that variable automatically, or use a short hold and swipe to make one inverse algebra move yourself. When every required value is known, the result appears immediately. For multi-step problems, carry a solved quantity into a related formula and keep the calculation on the same working blackboard. Formula search surfaces useful next equations when a result can feed another step. Teacher-style worked examples combine the physical story, a labeled visual, symbolic rearrangement, substitution, units, and interpretation. Narration and the visual presentation move together so you can follow the reasoning instead of only seeing a final answer. Included: • 200 Physics I and Physics II equations • Plain-English, symbol, quantity, and topic search • Interactive variable tiles with fixed units • Automatic isolation and step-by-step algebra gestures • Live diagrams and variable explanations • Narrated worked examples • Multi-formula problem chains • A built-in How to Use guide • On-device progress and settings • Core learning content available without an internet connection Charged Physics Lab is a learning and calculation aid. Always use the assumptions and sign conventions appropriate to your course and problem.