IGCSE Physics questions and answers

109 Cambridge IGCSE Physics questions answered by Eng. Ahmed Sherif (Shefo), written the way the mark scheme wants them.

Motion, Forces and Energy

• What is the difference between speed and velocity?
• How do you find acceleration from a speed time graph?
• What does the area under a speed time graph tell you?
• Why does a falling object reach terminal velocity?
• What is the difference between mass and weight?
• How do you calculate the resultant force?
• Why does a crumple zone reduce the force in a crash?
• How do you calculate efficiency?
• What is the difference between kinetic and gravitational potential energy?
• Why is energy never lost?

Thermal Physics

• Why does the temperature stay constant during boiling?
• Why does a gas exert pressure on its container?
• What happens to gas pressure when you heat it at constant volume?
• Why does hot water rise in a beaker?
• Which surface is the best emitter of infrared radiation?
• Why does evaporation cool a liquid?
• What is specific heat capacity?
• Why can thermal energy not travel by conduction through a vacuum?
• What is the difference between conduction, convection and radiation?

Waves

• What is the difference between transverse and longitudinal waves?
• Does the frequency change when a wave refracts?
• Why does light bend when it enters glass?
• Where do you measure the angle of incidence from?
• What is the critical angle?
• When does total internal reflection happen?
• How does an optical fibre work?
• What is the order of the electromagnetic spectrum?
• Why can sound not travel through a vacuum?
• How do you calculate the speed of a wave?

Electricity and Magnetism

• Is the current the same everywhere in a series circuit?
• How does current behave in a parallel circuit?
• Where do you connect an ammeter and a voltmeter?
• Why is the total resistance smaller when resistors are in parallel?
• How does a transformer work?
• Why does the national grid use high voltage?
• What is the motor effect?
• How do you induce a voltage in a wire?
• What is the difference between voltage in series and in parallel?
• How do you calculate electrical power?

Nuclear Physics

• What are alpha, beta and gamma?
• What stops alpha, beta and gamma radiation?
• Which type of radiation is the most ionising?
• What is an isotope?
• What is half life?
• Why must you subtract background radiation?
• What happens to the nucleus in alpha decay?
• What happens in beta decay?
• Is radioactive decay predictable?

Space Physics

• What is the order of the planets from the Sun?
• Why do outer planets take longer to orbit?
• What keeps a planet in orbit?
• Is a satellite in a stable orbit accelerating?
• What is the life cycle of a star like the Sun?
• What happens to a star much more massive than the Sun?
• What is redshift and what does it show?
• Does the Sun burn?
• How long does light take to reach Earth from the Sun?

Momentum

• What is momentum?
• Is momentum conserved in a collision?
• How do you solve a collision question?
• What happens in a sticky collision?
• What is impulse?
• Why do airbags reduce injury?
• Does direction matter in momentum calculations?
• How is force related to momentum?

Moments and the Turning Effect of Forces

• What is a moment?
• What is the principle of moments?
• Which distance do you use in a moment calculation?
• What is the centre of gravity?
• How do you find the centre of gravity of an irregular shape?
• What makes an object stable?
• When does an object topple?
• What are the units of a moment?
• Do you include the weight of the beam?

Refraction and Total Internal Reflection

• What is refraction?
• Which way does light bend when it enters glass?
• What is refractive index?
• What is Snell law?
• What is the critical angle?
• When does total internal reflection happen?
• How do optical fibres use total internal reflection?
• Does the ray leaving a rectangular glass block stay parallel to the ray entering?
• Does the frequency of light change during refraction?

Electromagnetic Induction and Transformers

• How do you induce a voltage in a conductor?
• Does a magnet sitting still inside a coil induce a voltage?
• What increases the size of the induced voltage?
• How does a generator work?
• Why does a transformer not work on direct current?
• What is the transformer equation?
• What is a step up transformer?
• Why does the grid transmit at high voltage?
• Does a transformer create energy?

Half Life and Radioactive Decay

• What is half life?
• How do you read half life from a graph?
• Why do you subtract the background count?
• How do you calculate activity after several half lives?
• Can you change the half life of a source?
• Is radioactive decay random?
• Does a radioactive source ever stop being radioactive?
• What is count rate?

Density and Pressure

• What is density?
• How do you measure the density of an irregular solid?
• Why do objects float?
• How do you convert grams per cubic centimetre to kilograms per cubic metre?
• How do you calculate pressure?
• Why do sharp knives cut better than blunt ones?
• Why does pressure increase with depth in a liquid?
• Does the shape of the container affect the pressure at a given depth?
• Does pressure in a liquid act in all directions?