OCR GCSE Physics A, Higher tier sample questions and answers (J249)
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40 sample questions and answers
Taken from every topic of OCR GCSE Physics A, Higher tier, specification J249. The full guide has 1,584.
Paper 3
Electricity
169 questions in the guide, across 10 subtopics. More from this topic
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Charge, and producing static electricity
An object has more electrons than protons. What is the sign of its overall charge?
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Negative, because the negative charge is no longer balanced by the positive charge. -
Transfer of electrons, and electric fields
Why are the charges on the two objects always equal in size and opposite in sign after rubbing?
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No charge is created or destroyed; the electrons one object gains are exactly the electrons the other object loses. -
Current as a rate of flow of charge
A closed loop of copper wire on its own carries no current. Which condition is missing?
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There is no source of potential difference to push the charge round. -
Charge, current and time
A charge of 90 C passes a point in 30 s. What is the current?
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3 A, because 90 C ÷ 30 s = 3 A. -
Series and parallel circuits, and circuit symbols
A cell supplies two branches, one carrying 0.4 A and the other 0.6 A. What current comes out of the cell?
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1.0 A, because the branch currents add up to the current from the cell.
Paper 4
Energy
101 questions in the guide, across 6 subtopics. More from this topic
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Conservation of energy, and energy stores
A toy car is given a push along a bench and eventually stops. Account for its energy as a closed system.
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The energy in its kinetic store has been transferred to the thermal stores of the car, the bench and the air, so the total is unchanged. -
Conservation of energy, and energy stores
A constant force pushes a trolley along a smooth level track. Describe the change in the way energy is stored.
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The force does work on the trolley, filling its kinetic store as it speeds up. -
Energy changes on heating, and calculating them
A heavy box is dragged at a steady speed across a rough floor. Describe the energy change taking place.
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Work is done against friction, transferring energy to the thermal stores of the box, the floor and the surrounding air. -
Energy changes on heating, and calculating them
A heater draws a current of 5 A from a 230 V supply for 60 s. How much energy is transferred?
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69000 J. -
Energy of a moving body, a spring and a raised object
A trolley of mass 8 kg has 100 J in its kinetic store. What is its speed?
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5 m/s.
Paper 3
Forces
374 questions in the guide, across 22 subtopics. More from this topic
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Measuring distance and time, and calculating speed
A cyclist travels 450 m in 30 s. What is her average speed?
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450 ÷ 30 = 15 m/s. -
Vectors and scalars in motion
What must be stated for a velocity to be fully described?
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Both its size, such as 15 m/s, and its direction, such as south. -
How objects interact, and forces as vectors
When two objects interact, how many forces are produced?
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Two, one acting on each of the two objects. -
Resolving forces, and free body diagrams
Why does the acceleration of a falling skydiver get smaller as she speeds up?
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Air resistance grows as her speed grows, so the downward resultant force becomes smaller. -
Momentum, and force as a change in momentum
A 2 kg trolley moving at 3 m/s collides with a stationary 4 kg trolley and they move off joined together. What is their velocity afterwards?
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The total momentum of 6 kg·m/s is now carried by 6 kg, so they move at 1 m/s.
Paper 4
Global Challenges
239 questions in the guide, across 13 subtopics. More from this topic
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Typical speeds and everyday accelerations
What does an acceleration of 2 m/s² mean in words?
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The speed increases by 2 m/s during every second. -
Reaction time, stopping distance and the dangers of large decelerations
Why can braking too hard cause a vehicle to skid?
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If the braking force demanded is greater than the friction the tyres can provide, the wheels lock and the vehicle slides, so the driver loses steering control and the stopping distance increases. -
Energy resources, and trends in their use
Why is biofuel counted as renewable when burning it releases carbon dioxide?
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The crops or waste it is made from can be regrown, and growing plants absorb carbon dioxide, so the resource is replaced as it is used. -
The national grid, and step-up and step-down transformers
Where in the grid is a step-down transformer found?
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At substations, between the transmission cables and the local supply to consumers. -
Mains electricity: a.c., d.c. and the domestic supply
Why is the mains supply dangerous to touch?
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About 230 V is large enough to drive a current through a person that can stop the heart or cause burns.
Paper 3
Magnetism and Magnetic Fields
135 questions in the guide, across 8 subtopics. More from this topic
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Permanent and induced magnets, and magnetic poles
Describe the field lines in the gap when a north pole and a south pole are placed facing each other.
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They run straight across the gap from the north pole to the south pole, linking the two magnets together. -
Magnetic fields, and the dipping compass
How does a plotting compass show the direction of a magnetic field at a point?
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Its needle turns until the north end points along the field line at that point. -
The magnetic effect of a current, and solenoids
What two things decide the strength of the magnetic field at a point near a straight current-carrying wire?
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The size of the current and the distance from the wire. -
The motor effect and Fleming's left-hand rule
Give two ways of increasing the force on a current-carrying wire in a magnetic field.
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Increase the current in the wire, or use a stronger magnetic field. -
The force on a conductor, and how a motor turns
A wire of length 0.60 m lies at right angles to a field of magnetic flux density 0.15 T and feels a force of 1.8 N. Calculate the current in the wire.
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The current is 20 A.
Paper 3
Matter
207 questions in the guide, across 11 subtopics. More from this topic
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How the atomic model changed, and the structure of the atom
Why do accepted scientific models such as the model of the atom change over time?
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New experimental evidence appears that the existing model cannot explain, so the model has to be revised or replaced. -
The size of atoms, and defining density
Why are the sizes of atoms usually written in standard form?
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Their size is about 1 × 10⁻¹⁰ m, which written out in full as a decimal would be a long and awkward number. -
Density of the states of matter, and density calculations
How is the density relationship rearranged to find volume?
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Volume is equal to mass divided by density. -
Conservation of mass in changes of state
What happens to the total mass of a substance when it melts, and why?
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The mass is unchanged, because exactly the same particles are still present and none are created or destroyed. -
Heating a system, and specific heat capacity
A beaker of water is heated steadily. Its temperature rises until it boils and then stops rising. Explain why.
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Before boiling the energy raises the kinetic energy of the particles, but at the boiling point it separates the particles instead, so the temperature holds steady.
Paper 4
Radioactivity
139 questions in the guide, across 9 subtopics. More from this topic
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Protons, neutrons and isotopes
What is an isotope?
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An isotope is an atom of an element that has the usual number of protons but a different number of neutrons. -
Unstable nuclei and the emissions they give out
What is the charge on an alpha particle?
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It has a charge of +2, because it carries two protons and no electrons. -
Balancing nuclear equations
Which two totals must be the same on both sides of a nuclear decay equation?
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The total mass number and the total charge must be the same on each side. -
Electron energy levels, and radiation from atoms
What charge does an atom have once it has lost an outer electron?
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It has a positive charge, because it then has more protons than electrons. -
Half-life and the randomness of decay
Does the half-life of a source change as more and more of its nuclei decay away?
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No, the half-life stays the same throughout, even though the number of undecayed nuclei is falling.
Paper 4
Waves in Matter
220 questions in the guide, across 15 subtopics. More from this topic
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Amplitude, wavelength, frequency and period
How does the amplitude of a wave relate to the energy it transfers?
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A wave of larger amplitude transfers more energy. -
The wave equation
Water waves travel at 0.2 m/s with a frequency of 4 Hz. What is their wavelength?
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The wavelength is 0.05 m, because 0.2 ÷ 4 = 0.05. -
Sound crossing a boundary; reflection, transmission and absorption
In which state of matter does sound normally travel fastest?
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In solids, because the particles are closest together and pass the vibration on most quickly. -
Converting sound to vibrations, and the range of hearing
What name is given to sound above the range of human hearing?
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Ultrasound. -
Electromagnetic waves as transverse, and energy transfer
In an electromagnetic wave, in what direction are the oscillations?
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At right angles to the direction in which the wave is travelling.
OCR GCSE Physics A, Higher tier Active Recall Guide
The other 1,544 questions, with the answers printed after each section.