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6 Particles and medical physics

7 dot points across 7 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How does a capacitor store charge and energy, and how does it discharge through a resistor?

Capacitors: capacitance and the farad, capacitors in series and parallel, the energy stored in a capacitor, and the exponential charge and discharge through a resistor with the time constant.
A focused answer to the OCR H556 capacitors content, covering capacitance and the farad, combining capacitors in series and parallel, the energy stored in a capacitor, and the exponential charging and discharging of a capacitor through a resistor with the time constant.
12 min answer →

How do electric charges exert forces at a distance, and how does an electric field compare with gravity?

Electric fields: Coulomb's law, electric field strength for radial and uniform fields, electric potential, and the comparison between electric and gravitational fields.
A focused answer to the OCR H556 electric fields content, covering Coulomb's law for the force between point charges, electric field strength for radial and uniform fields, the motion of charges in a uniform field, electric potential, and the parallels and contrasts between electric and gravitational fields.
12 min answer →

How does a changing magnetic field generate an electromotive force, and how do transformers work?

Electromagnetic induction: magnetic flux and flux linkage, Faraday's law of induction, Lenz's law, the emf induced in a moving conductor, and the operation of transformers.
A focused answer to the OCR H556 content on electromagnetic induction, covering magnetic flux and flux linkage, Faraday's law relating induced emf to the rate of change of flux linkage, Lenz's law and energy conservation, the emf induced in a moving conductor, and the operation of the ideal transformer.
12 min answer →

What force does a magnetic field exert on a current and on a moving charge?

Magnetic fields and the motor effect: magnetic flux density, the force on a current-carrying conductor, the force on a moving charge, and the circular motion of charged particles in a magnetic field.
A focused answer to the OCR H556 content on magnetic fields and the motor effect, covering magnetic flux density and its definition, the force on a current-carrying conductor with Fleming's left-hand rule, the force on a moving charge, and the circular motion of charged particles in a uniform magnetic field.
11 min answer →

How do X-rays, gamma cameras, PET and ultrasound let us see inside the body?

Medical imaging: the production and attenuation of X-rays, the gamma camera and PET scanning, and ultrasound with acoustic impedance and the Doppler effect.
A focused answer to the OCR H556 medical imaging content, covering the production of X-rays and their exponential attenuation, the gamma camera and PET scanning with positron annihilation, and ultrasound imaging with acoustic impedance, the intensity reflection coefficient and the Doppler effect for blood flow.
12 min answer →

What is the nucleus made of, and how do the standard model and binding energy explain matter and nuclear energy?

Nuclear and particle physics: alpha-particle scattering and the nuclear radius, the strong nuclear force, the standard model with quarks and leptons, beta decay, and mass-energy with binding energy, fission and fusion.
A focused answer to the OCR H556 nuclear and particle physics content, covering alpha-particle scattering and the nuclear radius equation, the strong nuclear force, the standard model with quarks and leptons, beta-minus and beta-plus decay with conservation laws, and mass-energy equivalence with binding energy, fission and fusion.
13 min answer →

How does radioactive decay follow an exponential law, and how are activity and half-life related?

Radioactive decay: the random and spontaneous nature of decay, the decay constant and activity, the exponential decay law, half-life and its relation to the decay constant, and radioactive dating.
A focused answer to the OCR H556 radioactive decay content, covering the random and spontaneous nature of decay, the decay constant and activity, the exponential decay law for the number of nuclei and activity, the relationship between half-life and the decay constant, and applications such as radioactive dating.
12 min answer →