Explain why a crack deep inside a metal block shows up in a test using waves.

The crack is a boundary between metal and air, so it reflects the wave back to the detector sooner than the far side of the block does.

What makes a sound wave an ultrasound wave?

Its frequency is higher than the upper limit of human hearing.

What happens to an ultrasound wave when it reaches a boundary between two different media?

It is partially reflected, so part of it returns and the rest carries on into the second medium.

How is the distance to a hidden boundary found using ultrasound?

The time for the reflected pulse to reach the detector is measured and used with the speed of the wave, halving the distance travelled because the pulse goes there and back.

Give one medical use of ultrasound.

Producing an image of an unborn baby in the womb.

AQA GCSE Physics 8463

Atomic Structure

Topic overview The structure of an atom Mass number, atomic number and isotopes From the plum pudding model to the nuclear model Chadwick, the neutron, and comparing the models Radioactive decay and nuclear radiation Nuclear equations Half-lives and the random nature of radioactive decay Radioactive contamination Background radiation Uses of nuclear radiation, and how half-life affects hazard Nuclear fission and nuclear fusion

Electricity

Topic overview Circuit symbols, electrical charge and current Current, resistance and potential difference Ohmic conductors, filament lamps, diodes and thermistors Light-dependent resistors, and investigating resistance Current and potential difference in series and parallel Constructing circuits, and calculating in series circuits Direct and alternating potential difference, and mains electricity Power and efficiency Appliances, and the energy transferred by electrical work Power, and the power ratings of domestic appliances The National Grid Static charge Electric fields

Energy

Topic overview Energy stores and systems Kinetic energy Elastic and gravitational potential energy Energy changes in systems Power Energy transfers in a system The main energy resources, renewable and non-renewable Environmental impact and trends in energy use

Forces

Topic overview Scalars, vectors, forces and the resultant force Gravity Work done and energy transfer Stretching, compressing, and the spring constant Linear and non-linear extension, and work done on a spring Moments, levers and gears Pressure at a surface, and the equation p = F over A Pressure in a column of liquid, upthrust and floating Atmospheric pressure Resolving forces and free body diagrams Distance, displacement and speed The speed of sound, and the distance-speed-time equation Velocity and the distance-time relationship Acceleration, deceleration and velocity-time graphs Area under a velocity-time graph, and the uniform acceleration equation Newton's First Law Newton's Second and Third Laws Stopping distance and reaction time Factors affecting braking distance Braking force, deceleration and the dangers of stopping quickly Momentum and its conservation Changes in momentum

Magnetism and Electromagnetism

Topic overview Poles of a magnet Magnetic fields around a magnet The compass, and plotting a magnetic field Electromagnetism Fleming's left-hand rule, motors and loudspeakers Induced potential The generator effect, alternators, dynamos and microphones The structure of a transformer and the turns ratio Transformer power, and using the transformer equations

Particle Model of Matter

Topic overview Density of materials Changes of state and internal energy Temperature changes in a system and specific heat capacity Changes of state and specific latent heat Particle motion in gases Pressure in gases, and increasing the pressure of a gas

Space Physics

Topic overview Our solar system, and the orbits of satellites The life cycle of a star Red-shift

Waves

Topic overview Transverse and longitudinal waves, and the wave equation Wave properties, and refraction at a boundary Reflection of waves Sound waves Ultrasound, echo sounding and seismic waves Types and uses of electromagnetic waves Radio waves, and the hazards of ultraviolet, X-rays and gamma rays Lenses Visible light Emission and absorption of infrared radiation, and black bodies

Waves

Ultrasound, echo sounding and seismic waves

3 things to know
Paper 2

Overview

Why waves reveal hidden structures, what makes sound ultrasound and how its partial reflection measures distance, its medical and industrial uses, echo sounding, and what P-waves and S-waves show about the Earth's core.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

Why can waves be used to explore structures that cannot be seen directly?

Evaluation

An ultrasound pulse travelling at 1500 m/s returns from a boundary 80 μs after it is sent. How far away is the boundary?

Key term

How do seismic waves give evidence about the size of the Earth's core?

Questions from this subtopic

Each one with the model answer underneath.

1
Why can waves be used to explore structures that cannot be seen directly?
Model answer
Different materials reflect and absorb waves differently and the waves travel through them at different speeds, so the returning waves carry information about what lies inside.
2
Explain why a crack deep inside a metal block shows up in a test using waves.
Model answer
The crack is a boundary between metal and air, so it reflects the wave back to the detector sooner than the far side of the block does.
3
What makes a sound wave an ultrasound wave?
Model answer
Its frequency is higher than the upper limit of human hearing.
4
What happens to an ultrasound wave when it reaches a boundary between two different media?
Model answer
It is partially reflected, so part of it returns and the rest carries on into the second medium.
5
How is the distance to a hidden boundary found using ultrasound?
Model answer
The time for the reflected pulse to reach the detector is measured and used with the speed of the wave, halving the distance travelled because the pulse goes there and back.
6
Give one medical use of ultrasound.
Model answer
Producing an image of an unborn baby in the womb.

See the rest and revise

Other ways to work this

The same content, four other ways.

What is inside Levo

Six ways to work the same material.

1Closed book

2Open book

3Closed book

The 3-step method, run for you

Answer cold, learn it, then prove it stuck. Levo tracks the jump between your first attempt and your last.

Atomic Structure

Electricity

Energy

Forces

Cram a whole paper in one sitting

Sort every topic into what you know and what you do not, then drill only the weak ones.

A wave.

transverselongitudinalmechanical

Blank Blitz makes facts automatic

Rapid timed gap-fills on the terms and numbers you need to recall without thinking.

AA cloud of dust and gas in space.

BThe force of gravity pulls the material together.

CThe material is pulled together tightly enough for nuclei to fuse.

Build It gets the exam shape right

Assemble a full-mark answer from its marking points, in the order an examiner wants them.

Moon means a natural body orbiting a planet.

TrueFalse

Test It catches misconceptions

Spot the fault in a statement. The traps are the mistakes students actually make.

721941163128510

Brain Breaks between sessions

Short focus games to reset attention, so the next set lands better than the last.

Every question in Waves, on a schedule.

Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.

Start revising, £5 a month See how the method works

Or £46 a year, about £3.83 a month. Cancel anytime.