Isotopes with a higher binding energy per nucleon will be more stable as it takes more energy to "split" the nucleus apart.

By applying an alternating current through the copper coil in the wireless charger, it induces a magnetic flux, and the magnetic flux will change due to AC changing the direction of the current.

The change in the magnetic flux, will allow the copper coil in the phone to have an induced current, and this current goes on to charge the battery pack in the phone.

An example of this would be a simple pendulum. It has a periodic oscillation, and the period of oscillation is proportional to the root of the length of the string. The restoring force is always in the direction of the equilibrium point, and is caused by gravity.

Another example would be a mass-spring system. It also has a periodic oscillation, but in real life, the dampening effect is more apparent. The restoring force is caused by the deformation of the string, and can be described by Hooke's Law. The point of equilibrium for this type of system is where the mass would be when the only force acting on a fixed spring is the weight of the mass.

For example, if I put a sheet of copper into a space where there is a magnetic field facing to the right, the current that is induced in the copper will be in the direction where the magnetic field generated by the current will be towards the left to counteract the change. We can find the direction of the current by using the right hand rule and the fact that the magnetic field generated must be facing the opposite direction of the existing field.

Another example that can show this is if a magnet was dropped through a conductive coil. As the falling magnet gets closer to the ring, it will induce a current in the coil to generate a magnetic field that repels the magnet, slowing the fall of the magnet. A similar case happens when the magnet falls away from the coil, the coil will want to oppose the change in the magnetic field field, wanting to keep the magnet near, so it will generate a magnetic field that attracts the magnet.

I think that this connection is easiest to show using a mass-spring system.

Where the restoring force is proportional to the displacement:

F = -kx

And connecting Faraday's law:

ε = -NdΦ/dt

We can see that both equations have a negative sign to show that it is opposing change, and that both are proportional to some change.

A magnetic field cause a current to be induced in a conductor.

A conductor with a current will induce a magnetic field.

If the magnetic field is in the same direction, it will strengthen the magnetic field.

Magnetic field becomes stronger, change in magnetic field continues to induce a current in the conductor, and then we will have infinite energy, which breaks physics (which would be revolutionary if it happened)

Therefore, Lenz's Law explains how energy is conserved as a current is induced in a conductor due to magnetic fields.

The direction of the induced EMF for the right and left position would be counter-clockwise.

The current from the battery will induce a magnetic field in the coil of the solenoid. This magnetic field will then induce a current, which will induce a secondary magnetic field around the wire.

Instantaneous velocity refers to the velocity at a certain point of time. This is usually expressed as the rate of change in displacement over time.

Average velocity refers to the velocity had the object been travelling at a constant speed, and can be expressed as the total displacement divided by the total time.

Velocity is also a vector quantity, refers to the rate of change of the displacement over time.

Acceleration is also a vector quantity, this is the rate of change of the displacement over time.

Some properties of the graphs if these values were graphed against time:

• If acceleration is constant, and non-zero

• Velocity would be a linear graph

• If acceleration is 0

• Velocity would be constant

• Displacement would be a linear graph

• Acceleration is 0

• Velocity is 0

• Displacement would be constant

However, it is more accurate to describe it as the rate of change in momentum over time, resulting in the following formula:

Therefore, it can be said that the net external force acting on an object is equal to the rate of change of the momentum of the object.

Lets say that there is a disc rotating at some speed, if we placed an object on the disc, the object gain some angular momentum due to the rotation of the disc, but the disc will lose some speed. The loss in angular momentum in the disc is equal to the gain in angular momentum in the object. In this case, angular momentum is conserved.

Area under a force vs distance graph = Work done

Area under a acceleration vs time graph = change in velocity

Area under velocity vs time graph = change in displacement

Area under power vs time graph = work done

We can find the amount of momentum being transferred from its impulse, which is the change in momentum. It is calculated by multiply the force by the interval of time the force is acted on the object.

• Molecules are in constant, random motion

• The particles have a negligible total volume

• No intermolecular forces

• The collisions between particles are perfectly elastic

Ek = 3/2(kB)T

Where kB is the boltzmann constant.

It is seen that the average kinetic energy is proportional to the temperature. I think that when heat is transferred to a molecule, we are giving it more kinetic energy, rather than thinking about heat and kinetic energy separately.

Consider the case where the greenhouse effect does not take place.

The energy transferred to the ground will have some of it reflected due to the albedo effect, and some energy is inputted into the earth. However, the input of energy into the Earth must equal to the output of energy from the earth. Therefore, there will be radiation from the ground back into the space, equal to the input that the earth received after considering the albedo effect.

However, heat loss or gain does not mean that there is no change in temperature, but instead refers to that there is no change to the internal energy of the system.

Adiabatic processes, when graphed, are usually steeper than isothermal processes.

Basically, lets say we have a circuit that is parallel. When the current reaches the point where it has to split into two different wires due to the parallel circuit, the sum of these two currents must be equal to the current that is entering the parallel circuit.

The implications of this is that we can excite the electron of an atom by giving it a specific amount of energy, and then after a while, it will deexcite and release the same amount of energy. The energy release and absorption usually happens in the form of photons of a specific wavelength.

If we give enough energy we are able to ionize the electron, ionized electrons will not go back to its ground state.

Shine light with enough energy on a metal surface and it will release electrons. Metals have a work function that is determined by what metal it is. The released electrons will have the energy of the light minus the work function of the surface.

We can also prevent electrons from being released if we run a conventional current in the direction of the electron's motion, then it will "decrease" the energy of the electrons. We call the voltage that completely stops the electrons from being ejected the stopping voltage, and it depends on the frequency of the light and/or the work function of the metal.

I think that if we made it such that the conventional current opposes the motion of the electrons, it would make the electrons go faster instead, and makes it easier to eject electrons, but I am not very sure.

Something to mention is that the further to the right you go, the lower the temperature, unlike conventional graphs.

Stars that are on the same diagonal line usually have the same size, and the main sequence stars usually have the same size, and are seen from the main diagonal of the diagram. Many supergiants are above the diagonal line of main sequence stars.

Of three of these quantities are vectors, and are all perpendicular to each other. For a positively charge, we say that the thumb is the direction of the velocity, the fingers (stretch out straight) are the magnetic fields, and the palm is the direction of the magnetic force.

Left hand rule is used for negative charges, the same rules applies here.

If we multiply it by r, we get the potential energy, which is similar to gravitational potential, as we multiply the force by some distance.

If we instead divide by one of the charges, we instead get the electric field strength, and this relates to the potential difference, as the field strength is simply the difference divided by some distance.

Pretty useful to know in tests in case i forget

If the source is moving towards the observer, perceived frequency will become higher, and results in a higher pitch.

Whereas if the source is moving away from the observer, the perceived frequency will be lower, and results in a lower pitch

This is commonly experienced when we hear the sirens of the ambulance. Sometimes I wonder if they did this intentionally to help drivers know if there is an ambulance coming towards them.

The closer the object, the faster it will need to rotate to be able to stay in orbit, otherwise it will just crash into the object it was orbiting.

This is usually connected back to E2 because we relate the energy of a photon with its wavelength.

When less dense to more dense:

Refracted light goes towards medium

When more dense to less dense:

Refracted light goes away from medium

When light travels from a much denser medium, something known as total internal reflection, where the light will be reflected back.

This happens at a large angle, and the angle where this will happen is the critical angle. The critical angle is where the angle of incidence will result in the refracted light to be 90 degrees away from the medium

There are three types of damping

• Critical damping

  • Goes back to its equilibrium position very fast without oscillating

• Light damping

  • Continues to oscillate, and will eventually return to equilibrium after a long time

• Heavy damping

  • Goes back to equilibrium without oscillating, but takes a long time.

However, if it was the case for a stationary source and an observer in motion instead, since the medium isn't squished together due to the motion of the source, the distance between the waves will remain the same, therefore the wavelength remains the same. However, because the observer will still be able to perceive a change in frequency

These are some of the more common cases:

• Stationary observer and source

• Stationary observer and source moving towards observer

• Stationary observer and source moving away from observer

• Observer moving towards stationary source

• Observer moving away from stationary source

Keep in mind of the direction of the velocity of the moving component because you don't want to perform the wrong operation (plus minus) during calculations.

The question is asking for the wavelength, which we can connect to the requirements for constructive interference, which the phase difference between the two sources must be a whole multiple of the wavelength out of phase.

After this, the phase difference that were given from the question and the phase difference that was caused by the path difference needs to be equal to some multiple of the wavelength.

The trick to this question is to recognize that there will be a larger shift in wavelength for larger wavelengths, therefore B is correct.

This is the angular equivalent to mass.

Apply kinematics equation for angles to find final velocity, in this case, we would want the equation without an angular displacement component as it is unknown.

• Shapes

• Discrete points

For shapes, we are usually given the formula.

For discrete points, we have to sum the moments for each of these points using the formula ML^2

Explain how is this possible.

Hint: 1. What stays constant during refraction and what changes?

2. Think about topic E1 atomic physics and the cause of colour.

Since angular displacement is given in radians, and there are 2pi radians in a full circle, we just take angular displacement divided by 2pi.

• “Using the first and second laws of thermodynamics, explain why Earth’s surface temperature is higher than the temperature predicted for a planet without an atmosphere.”

• Explain why the energy radiated by Earth has a much higher entropy than the energy received from the Sun, making reference to the number of available wavelengths.

For a real battery, we consider the internal resistance, whereas for an ideal battery, we assume that there is negligible or no internal resistance. The terminal voltage is the actual voltage of a source, so it considers any internal resistances that it may have, whereas emf is just the energy that is provided by the source.

For the change in temperature, external heat is required to be added to the system for isobaric expansion, using ideal gas law, so the change in temperature > 0. For adiabatic expansion, Q = 0, so since W > 0, then delta U < 0 must be true, since the internal energy of a monoatomic gas is related to its temperature, then the change in temperature must be negative as well.

V = ε - Ir

We want to find the displacement at time t, which is the dotted line. Notice that it mostly goes below the solid line, so its arrow would be down, which is a displacement to the left.

And for its velocity, since its displacement is to the left, then its velocity should be in the same direction as it was moving at time t.

Inertial reference frames refers to a non-accelerating reference frame (in a state of inertia), so either it is at rest, or staying at a constant velocity.

This is because if an experiment was conducted within a laboratory and in a moving ship, both experiments will yield the same result.

Take Newton's First Law for example, when a ship is moving at constant velocity, an object within the ship that was at rest will remain at rest, given that there is no external acceleration acting on the object.

The formula to calculate the position of an event would be given as:

x'=x-ut

Where u is the velocity measured in the stationary reference frame.

The position axes will change and the gamma factor is required as a factor compared to the galilean relativity

For the time axes, rather than using the time dilation formula, we need to use the Lorentz transformation for the time coordinates