Oscillations and waves
Simple harmonic motion
In the Standard Level waves section we established the definition of simple harmonic oscillations: the acceleration of an oscillating body is proportional to displacement but in the opposite direction. The AHL Waves requirements are more quantitative…
Oscillations and waves
Simple pendulum
…back towards the equilibrium position. If the swings are small, this force is proportional to the displacement, thus obeying simple harmonic motion. Essentials Consider the forces acting on a pendulum bob. We can show that, for small swings, the ac…
Oscillations and waves
…become stationary (and therefore transferring no energy at all). After studying this topic, you should be able to: Describe simple harmonic motion as an example of an oscillation, dispersion and guitar string frequencies Discuss how a force that is…
Oscillations and waves
AHL Waves
…nsions. What is the Doppler effect? What are the effects of a moving source, observer and medium? What are the equations for simple harmonic motion? How is the diffraction pattern formed for light passing through a single slit? What affects the inter…
Oscillations and waves
Equations for SHM
…he acceleration is proportional to displacement but in the opposite direction! However, we can verify that the condition for simple harmonic motion is obeyed by differentiating the original function for displacement twice with respect to time. Key C…
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AHL Damped and driven oscillations
In the Simple harmonic motion topic we considered natural oscillations of pendula and masses on springs. But so far we have ignored the effect of the fluid in which the oscillations are taking place and therefore the effects of damping. And what if t…
Daily IA
I really like this one. I common with most excellent investigation it's a simple idea but it turns out complex. On the face of it it's a too simple. What is the relationship between the resistance and length of a conductor. But this conductor is wide…
Electricity and magnetism
Kirchhoff's laws
Kirchhoff's laws are very useful for solving complex circuit problems but are based on simple conservation principles. Key Concepts Kirchhoff's first law The sum of the currents into a junction = the sum of the currents out: \(\sum I_{in}=\s…
Basics
Areas and volumes
Shapes and volumes are all around us all the time. Most objects can be modelled as something simple, or a combination. You will need to memorise the equations to obtain the areas of common shapes and it's worth learning the volumes too to save ch…
Oscillations and waves
Standing waves on a string
…n in a string but it doesn´t tell the whole story of wave properties. A string wave can't diffract or refract. Sometimes simple explanations cause misunderstandings. Here a string wave is polarised by a narrow slit. Light, however, is polarised b…
Atomic, nuclear and particles
Particle interactions
Particle interactions can be represented by Feynman diagrams governed by simple rules: One in, one out Two straight, one wiggly Key Concepts Conservation rules The following quantities must be conserved during particle interactions: Baryon number Lep…
Atomic, nuclear and particles
Structure of matter
Matter is vast and varied throughout the universe. Yet, zoom in enough and this complex story has a simple core - the Standard Model. This is good example of Occam´s razor. The simplest is most likely to be the correct solution. Particles interact…
Oscillations and waves
Oscillations
…asured in s). Frequency (f): The number of cycles per second (measured in Hz, which is equivalent to s-1) \(f={1\over T}\) Simple harmonic motion Simple harmonic motion is defined as motion where the acceleration is directly proportional to the dis…
Atomic, nuclear and particles
AHL Quantum
…ove outside an atom, a wave cannot move from a string clamped at both ends. A standing wave may only oscillate at particular harmonic frequencies; an electron may only have particular discrete energies. The kinetic energy of an electron is given by:…
Atomic, nuclear and particles
Atomic models
…ove outside an atom, a wave cannot move from a string clamped at both ends. A standing wave may only oscillate at particular harmonic frequencies; an electron may only have particular discrete energies. Substituting into the de Broglie wavelength equ…
Oscillations and waves
Mass on a spring
…easier to analyse, we do need to make the assumption that the mass and spring system is in space! This is another example of simple harmonic motion, as the acceleration is proportional to displacement and acting in the opposite direction. Summary We…
Revision tips
Mind maps and revision techniques
…some examples: Measurement and uncertainty - All Mechanics - All Mechanics - Bitesize Gallery: Mechanics - bitesize Mode: simple Thumb width: 128px Layout: row Thermal - All (and some bonus Engineering) Thermal - Bitesize Gallery: Thermal - bite…
Electricity and magnetism
Parallel resistors
…6 You then have one overall resistor in parallel with R7 What about light bulb filaments? So far we have considered only simple resistors that produce thermal energy. If these resistors are replaced with identical light bulb filaments, that with…
Electricity and magnetism
Resistance
In simple terms, resistance is opposition to the flow of current. It can be explained in terms of the atomic structure of matter. Resistance is defined as the ratio of potential difference through a conductor to the current flowing through it! Key C…
Electricity and magnetism
Potential difference
…ctise application of theory. Potential difference 28/02/2016 [SLIDES]: Multiple choice quiz on potential difference and the simple circuit …
Basics
Rearranging equations
…tion can be manipulated to make another quantity the subject of the equation. The videos below demonstrate how to rearrange simple equations. Key Concepts The order in which you would use an equation can be remembered as BODMAS: Brackets Other oper…
Circular motion and gravity
Centripetal force
…s the centre. This is because the change in direction implies that the body is accelerating. Deriving the equation is not so simple though... Key Concepts Perpendicular force A force acting at right angles to the direction of motion causes the body…
Electricity and magnetism
Coulombs law and field strength
Coulomb´s law is the electrical equivalent of Newton's law of gravitation. The universe is a simple place really! Key Concepts Coulomb's law The force between two point charges is proportional to the product of their charge and inversely pro…
Atomic, nuclear and particles
…s for circular motion for electron orbits that have quantised angular momentum. Find out more. What is quantum tunnelling in simple terms? Tunnelling is the term given to a particle passing through a potential energy barrier without having sufficient…
Atomic, nuclear and particles
Electron energy levels
…is similar to the path of a ball thrown on the Earth. This led to the idea that electrons are negatively charge particles. Simple model Atomic electrons can only have certain discrete values of positional energy (specific to the type of atom, based…
Energy production
Nuclear power I
…ens the reactor can not be shut down. Coolant (e.g. water) The kinetic energy of the fission products is transferred using a simple heat exchanger. A fluid passes on the other side of a barrier to the reactor at pressure produced by a pump. It increa…
Energy production
Renewable sources I
…ower station by using the steam to turn a turbine and generator. Hydroelectric The principle of hydroelectric power is quite simple. The potential energy stored in the water in high mountain lakes can be converted to electricity when the kinetic ener…
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Stellar quantities
…ckground. \(\tan p \approx p=\)1 AU / distance to near star Rearranging: distance to near star = 1 AU / \(p\) To make things simple the parsec is defined as the distance that subtends an angle of 1 arcsec. The distance to a star in parsec =\(1\over \…
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Rotational dynamics
…gm2) \(\alpha\) is angular acceleration (rads-2) It is important to consider how you might increase angular acceleration. In simple terms, \(\alpha = {\Gamma \over I}\), so angular acceleration increases with torque and decreases with moment of inert…
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Practical work
…Length of a Converging Lens Imaging only C.2 Investigating the Optical Compound Microscope Imaging only C.2 Investigating a Simple Optical Astronomical Refracting Telescope Group 4 Project The Group 4 Project contributes 10 hours to your practical w…
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Engineering
…tions of linear motion, we can derive equations for rotational motion. Find out more. What are the laws of thermodynamics in simple terms? The first law of thermodynamics states that the amount of heat that enters a closed gas container is equal to t…
Christmas tree lights puzzle
…transformer were arranged in parallel. The transformer gave an output of 3 V so the PD across each LED was 3V. It's not that simple though, what is the other wire for? I don't know so I had a closer look. Every now and again there are two with only 3…
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Cyclic processes
…tions that take the gas back to its original state. These form a closed loop on a \(pV\) diagram. Key Concepts Heat engine A simple cyclic process involves: Isobaric expansion - work is done on the surroundings Isovolumetric cooling Isobaric compress…
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Investigation handbook
…ic problem solving. After all, your IA is your investigation. Advice from investigation survivors "Your experiment should be simple and robust, not necessarily ground-breaking!" "It is good if you can produce a straight line graph. This enables you t…
Oscillations and waves
Single slit diffraction
…screen to be brightest in the centre and for the laser light to reduce in intensity outwards. In fact, the pattern is not so simple: the brightness minimises before increasing again. We can plot a graph of intensity against distance from the centre.…
Electricity and magnetism
Lenz's law
…use of uncertainty in whether to consider individual charges or the whole of the conductor. The good news is that there is a simple solution: since we know the consequence of Lenz's law is to oppose the change producing it, the resulting electrom…
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