List

PanPhO Problems and Solutions

Run by HKUST since 2005 for secondary schools across the Pan Pearl River Delta, and sat simultaneously in Shenzhen, Hong Kong and Macau. Papers are bilingual in English and Chinese, and divided into a part of shorter problems and a part of two or three long ones.

2026

Hong Kong

Short Problems4 problemsFull paperAll solutions
  • 1Rotating CylinderProblemSolution
    LaTeX transcriptionLaTeX source (.zip)Typeset PDF
  • 2Rods and PlanesProblemSolution
  • 3Transmission Line ModellingProblemSolution
  • 4The Thermodynamic Helmholtz ResonatorProblemSolution
Long Problems2 problemsProblemsSolutions
  • 5Current in a cylindrical wire*not published
  • 6Ponderomotive force and plasma equilibrium*not published

2025

Hong Kong

Short Problems4 problemsProblemsSolutions
  • 1Rolling lollipop angular momentum*not published
  • 2Laser tweezer forces on lenses*not published
  • 3Toroidal confinement of charged particles*not published
  • 4Harrison's Clock and Pendulum*not published
Long Problems2 problemsProblemsSolutions
  • 5Golfer’s Nightmarenot published
  • 6Ultrashort Gaussian pulse generation*not published

2024

Hong Kong

Short Problems4 problemsProblemsSolutions
  • 1Inhomogeneous cylinder oscillations*not published
  • 2Three-chamber gas mixing*not published
  • 3Charge in grounded spherical cavity*not published
  • 4Melting ice hemisphere laser deflection*not published
Long Problems2 problemsProblemsSolutions
  • 5Satellite laser interferometry errors*not published
  • 6Metric-modifiednot published

2023

Hong Kong

Short Problems4 problemsProblemsSolutions
  • 1Solar-powered satellite plate*not published
  • 2Binary suns with axial planet*not published
  • 3Light torque on rotating rod*not published
  • 4Piston oscillations in insulated cylinder*not published
Long Problems2 problemsProblemsSolutions
  • 5Vacuum bubblesnot published
  • 6Lorentz reciprocitynot published

2022

Hong Kong

Short Problems4 problemsProblemsSolutions
  • 1Block-spring on wedge*not published
  • 2Three-level Boltzmann system*not published
  • 3Wooden cylinder in two fluids*not published
  • 4Four-plate capacitor network*not published
Long Problems2 problemsProblemsSolutions
  • 5Spatiotemporal varying electric permittivitynot published
  • 6Fractal Dimensions of Networksnot published

2021

Hong Kong

Short Problems4 problemsProblemsSolutions
  • 1Rod on counter-rotating rollers*not published
  • 2Draining tank jet range*not published
  • 3Rotating charged magnetized sphere*not published
  • 4Atmospheric convection critical gradient*not published
Long Problems2 problemsProblemsSolutions
  • 5Quasicrystalsnot published
  • 6Black Hole Physicsnot published

2020

Hong Kong

Short Problems4 problemsProblemsSolutions
  • 1Gas expansion with piston*not published
  • 2Dust particle accreting mist*not published
  • 3Charged split metal sphere*not published
  • 4Apparent inner radius of glass tube*not published
Long Problems2 problemsProblemsSolutions
  • 5Precision measurement of the gravitational constant Gnot published
  • 6Physics in Various Dimensionsnot published

2019

Hong Kong

Short Problems4 problemsProblemsSolutions
  • 1A U-shaped glass tubenot published
  • 2Bug on a rodnot published
  • 3Falling magnet inside a conductive pipenot published
  • 4Heat flux between two platesnot published
Long Problems2 problemsProblemsSolutions
  • 5Gravitational Wavesnot published
  • 6Synchronizationnot published

2018

Hong Kong

Short Problems6 problemsProblemsSolutions
  • 1Length of Daytimenot published
  • 2Rotating Ballnot published
  • 3Nearest Exoplanet Discoverednot published
  • 4L-Shaped Conductor with a Wirenot published
  • 5A Flying Square Loopnot published
  • 6The Phenomenon of the Halonot published
Long Problems2 problemsProblemsSolutions
  • 7Oscillations of the Sunnot published
  • 8Plasmon Resonance and SERSnot published

2017

Hong Kong

Short Problems7 problemsProblemsSolutions
  • 1No-Shadow Daynot published
  • 2Six Missilesnot published
  • 3Falling laddernot published
  • 4Photon Gasnot published
  • 5Sea Surface Sound Transmissionnot published
  • 6Electron Trajectory in a Cavitynot published
  • 7Proton Motion Near a Charged Current-Carrying Wirenot published
Long Problems2 problemsProblemsSolutions
  • 8Bose Einstein Condensationnot published
  • 9Swimming Microorganismsnot published

2016

Hong Kong

Short Problems5 problemsProblemsSolutions
  • 1Electrostatic Forcenot published
  • 2Capacitorsnot published
  • 3Cannonballs and Bombsnot published
  • 4Collisionsnot published
  • 5Thermodynamic Cyclenot published
Long Problems3 problemsProblemsSolutions
  • 6Gravitational Lens Simulatornot published
  • 7A String and a Massnot published
  • 8Maximum Mass of a Starnot published

2015

Hong Kong

Problems7 problemsProblemsSolutions
  • 1Retrograde Motion of Marsnot published
  • 2Rolling Ball on a Racketnot published
  • 3Balloonnot published
  • 4Fresnel Biprismnot published
  • 5Ionic Crystalsnot published
  • 6Exoplanet Microlensingnot published
  • 7Cosmic Gravitational Wavesnot published

2014

Hong Kong

Problems8 problemsProblemsSolutions
  • 1Sunset Twice a Daynot published
  • 2Radiocarbon Datingnot published
  • 3Viscositynot published
  • 4Age of the Universenot published
  • 5Electrostatic Ion Thrustersnot published
  • 6Slinkynot published
  • 7DC Step-up Converternot published
  • 8White Dwarfnot published

2013

Hong Kong

Problems7 problemsProblemsSolutions
  • 1Bead collides with rod*not published
  • 2Binary star orbital motion*not published
  • 3Charge in conducting shell*not published
  • 4Apparent transverse speed of moving source*not published
  • 5Pumping a flat tire*not published
  • 6Inertia Inductance and Negative Refraction Mediumnot published
  • 7Gravitational Wavesnot published

2012

Hong Kong

Problems9 problemsProblemsSolutions
  • 1Neutrino mass from speed bound*not published
  • 2Pendulum with planar freedom*not published
  • 3Satellite after radial impulse*not published
  • 4Gyroscope precession angular velocity*not published
  • 5Charge near grounded hemisphere*not published
  • 6Piston expansion into vacuum*not published
  • 7Stella Interferometernot published
  • 8Y-Mesonnot published
  • 9Penning Trapnot published

2011

Hong Kong

Problems9 problemsProblemsSolutions
  • 1Compound pendulum and charged cart*not published
  • 2Electron momentum at three energies*not published
  • 3Capacitance of parallel cylinders*not published
  • 4Field energy density of sheets*not published
  • 5Privacy screen working principle*not published
  • 6Four-stroke cycle efficiency*not published
  • 7Neutrino Oscillationnot published
  • 8Bending Light with Gravitynot published
  • 9Magnetic monopolesnot published

2010

Hong Kong

Problems9 problemsProblemsSolutions
  • 1Mixed short physics problems*not published
  • 2Spacecraft orbit energy boost*not published
  • 3Point source through plano-convex lens*not published
  • 4Earth dipole field and wire force*not published
  • 5Diesel cycle efficiency*not published
  • 6Half disk flip impulse*not published
  • 7Chain Reactionsnot published
  • 8Quantum Gravitynot published
  • 9The Sound of Bubblesnot published

2009

Hong Kong

Problems8 problemsProblemsSolutions
  • 1Resistance and capacitance of layered plates*not published
  • 2Galaxy rotation curve exponent*not published
  • 3Block-spring on moving wedge*not published
  • 4EM wave in conducting medium*not published
  • 5Non-ideal gas Carnot cycle*not published
  • 6Early Solar Gas Distribution*not published
  • 7Spin torque on wire*not published
  • 8Nuclear magnetic resonance spin dynamics*not published

2008

Hong Kong

Problems9 problemsProblemsSolutions
  • 1Nuclear collision at right angle*not published
  • 2Moving dielectric slab magnetic field*not published
  • 3Spin and velocity alignment*not published
  • 4Atmospheric pressure with wind*not published
  • 5Rolling sphere over a ditch*not published
  • 6Effective mass of spring-block system*not published
  • 7Charged particle in radial magnetic field*not published
  • 8Electric fan stopping time*not published
  • 9Negative resistance device circuits*not published

2007

Hong Kong

Problems10 problemsProblemsSolutions
  • 1Weightless airplane trajectory*not published
  • 2Two masses on swinging rod*not published
  • 3Fields of magnetized disc and cylinder*not published
  • 4Moving dielectric slab in magnetic field*not published
  • 5Concentric shells with two media*not published
  • 6Adiabatic atmosphere and rain*not published
  • 7Torque on a medium by EM wave*not published
  • 8Folded space photon modes*not published
  • 9AFM thermal noise resonance*not published
  • 10Lorentz-Lorenz relation derivation*not published

2006

Hong Kong

Problems8 problemsProblemsSolutions
  • 1Electron-quark collision in meson*not published
  • 2Pulley with adjustable magnets*not published
  • 3Spinning vessel water pressure*not published
  • 4Two-compartment gas heat exchange*not published
  • 5Reflection at complex refractive index boundary*not published
  • 6Casmir Effectnot published
  • 7Electric Current Driven Magnetic Domain Movementnot published
  • 8Force between a conductor sphere and a conductor planenot published

2005

Hong Kong

Problems8 problemsProblemsSolutions
  • 1Worms climbing over each other*not published
  • 2Air bubble and tank rising*not published
  • 3Stone-throwing man on rotating disk*not published
  • 4Rod in a hemisphere*not published
  • 5EM wave in complex medium*not published
  • 6Coil falling through magnetic field*not published
  • 7Hall and spin-Hall effect*not published
  • 8Shear modulus of ER fluid*not published