AQA AS Physics Definitions Exam Questions
and Answers 100% Pass
Specific charge
the charge to mass ratio or charge in coulombs divided by the mass in kilograms
Isotope
a nucleus with the same number of protons but different number of neutrons
Hadron
a particle that experiences the strong nuclear force. Composite particles made of either qqq (baryons)
or q anti-q (baryon)
Antimatter
Particles with the same mass but opposite charge
Photoelectric effect
the emission of electrons from metal surfaces by light of an appropriate frequency
Photon
a discrete packet/quantum of electromagnetic energy
Work function
the minimum energy required for an electron to escape from the surface of the metal
Threshold frequency
the minimum frequency of a photon required to release electrons from the surface of a metal
Electron volt
the energy given to an electron when it passes through a potential difference of 1 V
Energy Level
Allowed/discrete energy of an atom or electron in an atom
Ionisation energy of an atom
the minimum energy required to remove an electron from an atom in its ground state
Excitation energy
the energy required to move an electron from a lower energy level to a higher energy level
Line spectra
the characteristic wavelengths of light produced by individual excited atoms
Longitudinal waves
, direction of oscillation is parallel to the direction of wave travel. Wave travels with series
compressions and rarefactions.
Transverse waves
direction of oscillation is perpendicular to the direction of wave travel with peaks and troughs.
Electromagnetic wave
a transverse wave, consisting of a changing magnetic field at right angles to a changing electric field
Amplitude
the maximum displacement from the equilibrium position
Frequency
the number of oscillations per second
Wavelength
the shortest distance between two consecutive particles in a wave which are in phase
Wave speed
the speed of energy transfer through the medium
Diffraction
Diffraction is the spreading out of a wave as it passes through an aperture/around an obstacle.
Polarised waves
electromagnetic waves where the oscillations are in one direction only that is 90° to the direction of
wave travel
Unpolarised waves
electromagnetic waves where the oscillations are in many directions
Refractive index
the absolute refractive index of the substance is the speed of light in a vacuum divided by the speed
of light in the substance, n = Vc/Vs
Critical angle
the angle of incidence on a boundary between two media when the angle of refraction is 90°
Total internal reflection
total internal reflection occurs when an EM wave goes from a more dense to less dense medium and
the angle of incidence is greater than critical angle. All the light is reflected within the substance
Step index fibre
there is a sudden change in refractive index between the core and the cladding
and Answers 100% Pass
Specific charge
the charge to mass ratio or charge in coulombs divided by the mass in kilograms
Isotope
a nucleus with the same number of protons but different number of neutrons
Hadron
a particle that experiences the strong nuclear force. Composite particles made of either qqq (baryons)
or q anti-q (baryon)
Antimatter
Particles with the same mass but opposite charge
Photoelectric effect
the emission of electrons from metal surfaces by light of an appropriate frequency
Photon
a discrete packet/quantum of electromagnetic energy
Work function
the minimum energy required for an electron to escape from the surface of the metal
Threshold frequency
the minimum frequency of a photon required to release electrons from the surface of a metal
Electron volt
the energy given to an electron when it passes through a potential difference of 1 V
Energy Level
Allowed/discrete energy of an atom or electron in an atom
Ionisation energy of an atom
the minimum energy required to remove an electron from an atom in its ground state
Excitation energy
the energy required to move an electron from a lower energy level to a higher energy level
Line spectra
the characteristic wavelengths of light produced by individual excited atoms
Longitudinal waves
, direction of oscillation is parallel to the direction of wave travel. Wave travels with series
compressions and rarefactions.
Transverse waves
direction of oscillation is perpendicular to the direction of wave travel with peaks and troughs.
Electromagnetic wave
a transverse wave, consisting of a changing magnetic field at right angles to a changing electric field
Amplitude
the maximum displacement from the equilibrium position
Frequency
the number of oscillations per second
Wavelength
the shortest distance between two consecutive particles in a wave which are in phase
Wave speed
the speed of energy transfer through the medium
Diffraction
Diffraction is the spreading out of a wave as it passes through an aperture/around an obstacle.
Polarised waves
electromagnetic waves where the oscillations are in one direction only that is 90° to the direction of
wave travel
Unpolarised waves
electromagnetic waves where the oscillations are in many directions
Refractive index
the absolute refractive index of the substance is the speed of light in a vacuum divided by the speed
of light in the substance, n = Vc/Vs
Critical angle
the angle of incidence on a boundary between two media when the angle of refraction is 90°
Total internal reflection
total internal reflection occurs when an EM wave goes from a more dense to less dense medium and
the angle of incidence is greater than critical angle. All the light is reflected within the substance
Step index fibre
there is a sudden change in refractive index between the core and the cladding
