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Why are some isotopes more stable than others?

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Why are some isotopes more stable than others?

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1. Higher binding energy

2. Larger isotopes need more neutrons to counteract repulsive forces between protons, explaining why for higher mass isotopes the neutron proton ratio is larger.

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photoelectric effect presentation notes 

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photoelectric effect presentation notes 

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intensity of light is directly proportional to the current generated by the photoelectric effect

Real life applications: solar panels

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moderators slow down fast-moving neutrons so that they are more likely to be absorbed by U-235 nuclei.

Control rods are used to absorb excess neutrons to control the rate of the reaction.

smaller nuclei formed are called fission products. they are usually radioactive. long half live means more hazardous due to environmental persistence.

nuclear fission as energy source has lower carbon footprint compared to natural gas, coal etc.

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By applying current to the coil inside the wireless charger, a magnetic field is generated, which is induced on the coil inside the phone, generating an electric current and thus charging the phone.

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Magnetic flux (symbol Φ, unit Weber/Wb) equals to magnetic field strength (B) multiplied by A (Area the field is passing through. For coil with radius r the A would be pi*r^2), and cos theta, with theta being the angle between magnetic field lines and the normal vector of the field.

Magnetic field strength B is called flux density, and the equation can be rearranged as B=Φ/(A cos theta). Flux over area = flux density.

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voltage required to stop electrons from moving between plates in the photoelectric effect.

In hf = Φ + KEmax, stopping voltage = KEmax.

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Flux linkage = N*(flux)

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Self inductance happens when you apply an alternative current through a conducting coil.

AC can be represented by a sine wave. Meaning that the direction of the magnetic field and subsequently the flux generated is constantly changing, creating an emf in the loop.

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frequency (f) refers to the numbers of oscillations/cycles per second, measured in Hertz (Hz). For example, 5 Hz means 5 oscillations/cycles per second.

Angular frequency (ω) refers to rate of change of an angle, measured in (rad/s)

Period (T) refers to the time it takes to complete one full cycle (for an oscillating object to return to its original location), measured in seconds.

The three units relate to each other in the following equation:

T (period) = 1/f (frequency) = 2π/ω (angular frequency)

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Spring-mass system: the period is affected by mass of the object (m) and the spring constant (k). Where T=2π√(m/k)

pendulum: in a pendulum in SHM, the period is affected by the length of the pendulum (l) and accelerating from gravity (g). Where T=2π√(l/g)

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velocity, frequency, wavelength and period

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velocity, frequency, wavelength and period

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velocity of a wave (v) is the rate of change of its position as it masses through a medium/space.

frequency (f) is the numbers of cycles performed by a wave per second, measured in Hertz (Hz)

wavelength (λ) is the distance between two consecutive corresponding point on a wave, like the distance between two consecutive crests or troughs. Measured in meters (m).

Period (T) is the time required for a wave to complete one full cycle. Like for a sine wave to go from 0 to 2π.

These four quantities relate to each other in the following equation:

v = fλ = λ/T

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Complete this ASAP (then ask for the worked solution)

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Complete this ASAP (then ask for the worked solution)

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A4 Rigid Body Motion Paper 2 Exam Question

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The angle of diffraction of the first minimum (θ) is given by the equation:

θ=λ/b

where:

λ = wavelength of incident light

b = slit width.

θ is inversely proportional to slit width (b). The narrower the slit, the wider the angle of diffraction, and vice versa.

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The component of the relative velocity along the line of sight (parallel to the line of sight)

i.e.

motion towards/away from the observer: parallel

sideway motion (across the observer's field of view): perpendicular.

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Δλ=λ(v/c)

This equation describes wavelength shifts due to relative motion along the line of sight.

Change in wavelength is directly proportional to the emitted wavelength.

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Moment of inertia is the measure of an object's resistance to changes of its rotational movement about a specific axis.

The image shows the moment of inertia for different objects on different axis of rotation.

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rotational equilibrium is when's zero resultant torque on an object, for example, when clockwise torque = counterclockwise torque.

The object either remain stationary or in constant angular velocity. The angular acceleration (rate of change of angular velocity) remains zero.

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Question from Teacher Joshua: changes during refraction?

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Question from Teacher Joshua: changes during refraction?

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When light passes across a boundary into water or glass in undergoes refraction. Refraction doesn’t change the colour of light, but its wavelength does change during refraction.

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.

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Important Graph 1: Draw the graph for magnitude of the electric field strength (E) vs distance (r)

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Important Graph 1: Draw the graph for magnitude of the electric field strength (E) vs distance (r)

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Important Graph 2: Draw the graph for magnitude of the electric field strength (E) vs distance (r)

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Important Graph 2: Draw the graph for magnitude of the electric field strength (E) vs distance (r)

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Solution posted as comment.

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Solution posted as comment.

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Solution posted as comment.

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An ideal battery has no internal resistance and maintains a constant emf, while a real battery has a non-zero internal resistance and experiences a drop in terminal voltage as the current increases.

Terminal voltage = emf - current * internal resistance.

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Solution posted as comment.

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Solution posted as comment.

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Total resistance = R/2 + R/2 + R = 2R

I = emf/R=12/2R = 6/R

V= IR = (6/R) * R = 6V (option C)

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Time dilation: change in time

Lorentz transformation: clock measurement at a particular position on the spacetime diagram.