IGCSE · International AS & A-Level
Physics questions,
explained.
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IGCSE Physics
Measurements and units
- Why do you time 20 oscillations instead of one?
- Do I need to memorize unit conversions for IGCSE physics?
- What is the difference between a scalar and a vector?
- Does repeating measurements remove a zero error?
- How do you avoid parallax error when reading a ruler?
- How can I measure the thickness of one sheet of paper accurately?
IGCSE Physics
Motion
- How do you explain terminal velocity for full marks?
- What does the gradient of a distance-time graph give?
- How do you find distance from a speed-time graph?
- Does negative acceleration always mean an object is slowing down?
- Can I find average speed by adding two speeds and dividing by two?
- Can an object be moving when its acceleration is zero?
IGCSE Physics
Mass, weight and density
- What is the difference between mass and weight in IGCSE physics?
- How do you find the density of an irregular object?
- Why does ice float on water?
- How do I convert density from g/cm³ to kg/m³?
- Why must I subtract the container's mass when measuring liquid density?
- How can a steel ship float if solid steel sinks?
IGCSE Physics
Forces
- What does a resultant force do to an object?
- How do you answer Hooke's law graph questions?
- Why does an object moving in a circle accelerate at constant speed?
- Why don't Newton's third-law forces cancel each other?
- Are the elastic limit and the limit of proportionality the same?
- Why does a car need a driving force if it is travelling at constant speed?
IGCSE Physics
Moments and turning effects
- How do you find the centre of gravity of a lamina?
- What makes an object stable?
- What are the two conditions for equilibrium?
- Which distance do I use when calculating a moment?
- When do I include a beam's weight in a moments calculation?
- Why does the support nearer a load carry more of its weight?
IGCSE Physics
Momentum
- How do crumple zones reduce injury?
- Is momentum always conserved?
- What is the connection between impulse and momentum?
- How do I calculate the final velocity when two objects stick together?
- How can momentum be conserved when kinetic energy is not?
- Why is a ball's momentum change larger when it rebounds than when it stops?
IGCSE Physics
Energy, work and power
- What are the energy stores in IGCSE physics?
- How do you calculate efficiency?
- What is the difference between work and power?
- Why does mgh use vertical height rather than the length of a ramp?
- Why does doubling speed quadruple kinetic energy?
- Where does wasted energy go if energy is conserved?
IGCSE Physics
Pressure
- Why are dam walls thicker at the bottom?
- Why does a sharp knife cut better than a blunt one?
- Does the shape of a container affect liquid pressure?
- Why must I divide cm² by 10,000 when calculating pressure in pascals?
- When should I add atmospheric pressure to ρgh?
- How do I find the net force when pressure acts on both sides of a surface?
IGCSE Physics
The particle model of matter
- How do you describe the three states of matter for full marks?
- Why does gas pressure increase with temperature?
- What does Brownian motion prove?
- What graph shows that gas pressure is inversely proportional to volume?
- What is the difference between diffusion and Brownian motion?
- Do particles get bigger when a substance is heated?
IGCSE Physics
Thermal properties of matter
- Why does temperature stay constant during melting?
- Why does evaporation cool a liquid?
- What factors increase the rate of evaporation?
- Why do heat losses make a measured specific heat capacity too high?
- Do I need to convert Celsius to kelvin in specific heat capacity calculations?
- What is the difference between boiling and evaporation?
IGCSE Physics
Heat transfer
- Why are metals better conductors than non-metals?
- Why are radiators painted... and should they be black?
- How does the Sun's energy reach Earth?
- Why does a vacuum flask need shiny walls as well as a vacuum?
- Why is water usually heated from below in convection experiments?
- What variables should I control in an insulation cooling experiment?
IGCSE Physics
General wave properties
- What is the difference between transverse and longitudinal waves?
- What happens to frequency during refraction?
- When is diffraction most noticeable?
- How do I tell whether a wave graph gives period or wavelength?
- Does reflection change a wave’s speed, frequency or amplitude?
- How can a wave transfer energy without transferring matter?
IGCSE Physics
Light
- How do optical fibres work?
- How do you draw a converging lens ray diagram?
- When does a converging lens act as a magnifying glass?
- Why must refraction angles be measured from the normal?
- What is the difference between a real image and a virtual image?
- Why is a ray emerging from a rectangular glass block parallel to the incident ray?
IGCSE Physics
The electromagnetic spectrum
- What is the order of the electromagnetic spectrum?
- Which electromagnetic waves are dangerous and why?
- Why are microwaves used for satellite communication?
- Do gamma rays travel faster than radio waves?
- How do I convert a wavelength in nanometres into frequency?
- How can an infrared camera show objects in the dark?
IGCSE Physics
Sound
- Why does sound travel faster in solids than in gases?
- How does sonar measure depth?
- What changes on an oscilloscope trace when a sound gets louder and higher-pitched?
- Why do I not divide by two when measuring sound speed with two microphones?
- Does ultrasound travel faster than audible sound?
- Why can light travel through space but sound cannot?
IGCSE Physics
Magnetism
- How do you test whether a bar is magnetised?
- Why is soft iron used in electromagnets?
- How can you increase the strength of an electromagnet?
- Why can magnetic field lines never cross?
- Are all metals magnetic because they conduct electricity?
- How do I map a magnetic field using a plotting compass?
IGCSE Physics
Static electricity
- Why do friction experiments transfer electrons rather than protons?
- Why are fuel tankers earthed before unloading?
- Can a charged balloon stick to an uncharged wall?
- Do electrons always flow to Earth when an object is earthed?
- Can a conductor be charged, or only an insulator?
- Why does an electron experience force opposite to the electric field?
IGCSE Physics
Electric circuits
- What are the series and parallel circuit rules?
- Why does adding resistors in parallel decrease total resistance?
- What is the difference between e.m.f. and potential difference?
- Why is a filament lamp’s current–voltage graph curved?
- Why are ammeters connected in series and voltmeters in parallel?
- Does increasing resistance increase or decrease electrical power?
IGCSE Physics
Electromagnetic effects
- How do you increase the e.m.f. induced in a coil?
- Why is electricity transmitted at high voltage?
- What is the difference between a split-ring commutator and slip rings?
- Why does a transformer not work continuously on steady d.c.?
- What happens to induced current when the magnet’s motion is reversed?
- What happens to motor force if both current and field are reversed?
IGCSE Physics
Radioactivity
- What are the properties of alpha, beta and gamma radiation?
- How do you calculate half-life from a graph?
- Why is gamma used for medical tracers?
- Does all radioactive material disappear after two half-lives?
- What is the difference between irradiation and radioactive contamination?
- How can beta-minus radiation be an electron if it comes from the nucleus?
IGCSE Physics
Space physics
- Is space physics in Cambridge IGCSE Physics 0625?
- How did the Solar System form?
- How do redshift and the cosmic microwave background support the Big Bang?
- Why is a main-sequence star stable?
- Should I use altitude or distance from Earth’s centre for orbital speed?
- Why does one divided by the Hubble constant estimate an age?
Edexcel IAL · AS
Physical quantities and units
- What is the difference between random and systematic error?
- How do you combine uncertainties at A-Level?
- What does checking homogeneity mean?
- Why can a small extension have a large percentage uncertainty?
- How do I choose sine or cosine when resolving a vector?
- When should I round answers in A-level physics calculations?
Edexcel IAL · AS
Kinematics
- When can you use the SUVAT equations?
- How do you approach projectile questions?
- How is g measured in the lab?
- How do negative areas on a velocity–time graph affect distance and displacement?
- Why is acceleration not zero at the highest point of a projectile?
- How do I find instantaneous velocity from a curved displacement–time graph?
Edexcel IAL · AS
Dynamics
- What makes a valid Newton's third law pair?
- Is momentum conserved in inelastic collisions?
- Why is F = Δp/Δt more fundamental than F = ma?
- How do I find impulse and average force from a force–time graph?
- Does an object’s weight change when it reaches terminal speed?
- Which mass should I use for connected objects, and where does tension go?
Edexcel IAL · AS
Forces, moments and equilibrium
- What are the conditions for equilibrium?
- What is a couple in physics?
- How do you choose the pivot in a moments problem?
- How do I calculate a moment when the force is at an angle?
- How do centre of gravity and base width determine when an object tips?
- What forces should I draw at smooth and rough contacts?
Edexcel IAL · AS
Work, energy and power
- When does a force do no work?
- How do you derive kinetic energy = ½mv²?
- Why does maximum speed occur when driving force equals resistance?
- How do I find work done when the force changes with displacement?
- Can gravitational potential energy be negative in an energy calculation?
- When should I use energy efficiency rather than power efficiency?
Edexcel IAL · AS
Deformation of solids
- What is the difference between the limit of proportionality and the elastic limit?
- How is strain energy calculated?
- Why does measuring the diameter dominate the uncertainty in a Young modulus experiment?
- How do wire length and thickness affect extension?
- What is the difference between stiffness, strength and toughness?
- How do I calculate Young modulus from a force–extension graph?
Edexcel IAL · AS
Waves and superposition
- What conditions are needed for observable interference?
- How is a stationary wave different from a progressive wave?
- Why does a diffraction grating give sharper maxima than a double slit?
- Why are adjacent nodes half a wavelength apart?
- How do I convert a path difference into a phase difference?
- What is the difference between diffraction and interference?
Edexcel IAL · AS
Electricity and d.c. circuits
- What is internal resistance and why does it matter?
- How does a potential divider with a thermistor work?
- What do Kirchhoff's laws conserve?
- How do I find emf and internal resistance from a V–I graph?
- Why does connecting a load change a potential divider’s voltage?
- What is the difference between resistance and resistivity, and why does temperature matter?
Edexcel IAL · A2
Circular motion
- What provides the centripetal force?
- Why is there acceleration if the speed is constant?
- What is the minimum speed at the top of a vertical circle?
- Why is string tension greater at the bottom of a vertical circle?
- How do I convert rpm into angular speed and tangential speed?
- Does increasing the radius increase or decrease centripetal force?
Edexcel IAL · A2
Gravitational fields
- Why is gravitational potential negative?
- How do you find the speed of an orbiting satellite?
- Why must geostationary satellites orbit over the equator?
- Why must I add the planet’s radius to a satellite’s altitude?
- Why do astronauts feel weightless if gravity keeps them in orbit?
- When does mgh stop being a good approximation?
Edexcel IAL · A2
Temperature and ideal gases
- How is temperature related to molecular kinetic energy?
- What are the assumptions of the kinetic theory of gases?
- Why does the internal energy of an ideal gas depend only on temperature?
- Why can Celsius be used for a temperature change but not in a gas-law ratio?
- Which graph should I plot to test Boyle’s law?
- Why can heating continue without the temperature rising during a phase change?
Edexcel IAL · A2
Oscillations
- What does the minus sign in a = −ω²x mean?
- Where are speed and acceleration greatest in SHM?
- What is resonance and when is it a problem?
- How do I find the SHM period from an acceleration–displacement graph?
- Does a larger amplitude change period, speed or energy?
- How can I improve a pendulum-period experiment?
Edexcel IAL · A2
Electric fields
- How are electric and gravitational fields similar and different?
- When do you use E = V/d versus the inverse-square formula?
- What path does a charged particle take in a uniform electric field?
- Can electric field be zero where electric potential is not zero?
- Why does an electron accelerate towards the positive plate or higher potential?
- Why do field lines cross equipotential surfaces at right angles?
Edexcel IAL · A2
Capacitance
- Why is the energy stored ½QV and not QV?
- What does the time constant tell you?
- Why do capacitor combination rules look inverted compared to resistors?
- How do I find RC from a logarithmic discharge graph?
- Which plate’s charge is Q in the capacitance equation?
- Why can a voltmeter change the measured capacitor discharge time?
Edexcel IAL · A2
Magnetic fields
- Why does a charge move in a circle in a magnetic field?
- How does a velocity selector work?
- What does the Hall effect measure?
- How can a magnetic field accelerate a particle but do no work?
- What determines the radius of a charged particle’s path in a magnetic field?
- How do I find the magnetic force direction on an electron?
Edexcel IAL · A2
Electromagnetic induction
- What is the difference between flux and flux linkage?
- How does Lenz's law follow from conservation of energy?
- Why does dropping a magnet through a copper tube slow it down?
- How do I find induced emf from a flux-linkage graph?
- Why is generator emf zero when magnetic flux is maximum?
- Which angle belongs in the magnetic flux formula?
Edexcel IAL · AS
Quantum physics
- Why does the photoelectric effect require a photon model?
- What is the evidence that electrons behave as waves?
- Why do line spectra support discrete energy levels?
- How do intensity and frequency affect photoelectric current and electron energy differently?
- What is stopping potential, and what does its frequency graph show?
- Why do different metals have different photoelectric threshold frequencies?
Edexcel IAL · A2
Nuclear physics
- Where does the energy in fission and fusion come from?
- What is the relationship between half-life and the decay constant?
- Why is radioactive decay exponential?
- Why is detector count rate different from activity?
- Why use binding energy per nucleon instead of total binding energy?
- Why is an antineutrino included in beta-minus decay?
Edexcel IAL · A2
Astrophysics and cosmology
- Which Edexcel IAL Physics paper includes astrophysics and cosmology?
- How does the H–R diagram show a star's life cycle?
- How can a hotter star have the same luminosity as a cooler star?
- What does dark matter change in models of the Universe?
- Why do I halve the six-month angular shift in a parallax calculation?
- Why is 1/H₀ only an approximate estimate of the age of the Universe?
Build the whole picture
The answers link back to full lessons, definitions and practice. IGCSE notes cover shared Cambridge and Edexcel concepts; AS and A2 notes focus on Edexcel International A-Level. Check each topic’s course notes and your official specification for exact requirements.