Fields, Particles And Frontiers Definitions Flashcards
Coulomb’s law
Any two point charges exert an electrical force on each other that is proportional to the product of their charges and inversely proportional to the square of the distance between them
Electric field strength
At a point is the force per unit charge exerted on a positive charge placed at that point
Magnetic flux density/Tesla
The magnetic flux density is 1T when a wire carrying a current of 1A placed at right angles to the magnetic field experiences a force of 1N per metre of its length
Magnetic flux
The product of magnetic flux density normal to a circuit and the cross-sectional area of the circuit
Faraday’s law
The magnitude of induced e.m.f. Is equal to the rate of change of magnetic flux linkage
Lenz’s law
Any induced current or e.m.f. will be established in a direction so as to produce effects which oppose the change producing it
Capacitance
Of a capacitor is the charge stored per unit of potential difference across it
Time constant
Is the time taken for the current, charge stored or p.d. to fall to 1/e (=37%) of its initial value
Isotopes
Nuclei of the same element with a different number of neutrons but same number of protons
Mass defect
Of a nuclei is equal to the mass difference between the total mass of the individual separate nucleons and the mass of the nucleus
Binding energy
Of a nucleus is the minimum energy needed to pull apart a nucleus into its separate nucleons
Decay constant
The probability that an individual nucleus will decay per unit time interval
Activity
Of a radioactive sample is the rate at which nuclei decay
Half-life
Of a radioisotope is the mean time taken for half of the active nuclei in a sample to decay
Intensity
The power per unit cross-sectional area
