EXAM 2025 WITH MULTIPLE CHOICE OF
QUESTIONS AND DETAILED SOLVED
SOLUTIONS ALREADY GRADED A+ AND 100%
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Explain how (bright ring) diagram is evidence of the wave-
particle duality of electrons? - CORRECT ANSWER-Diffraction pattern
maxima/minima (bright and dark areas) (1)
Diffraction is a property of waves- proves wave-behaviour of
electrons (1)
What is meant by the ground state? - CORRECT ANSWER-The lowest
energy state of an atom
Explain the difference between excitation and ionisation (2) -
CORRECT ANSWER-An electron receives a discrete amount of energy
for BOTH (1)
Excitation promotes an electron to a higher energy level
Ionisation is when an electron receives enough energy to leave
the atom
Explain why only photons of certain frequencies cause
excitation (4) - CORRECT ANSWER-discrete energy levels (1)
, Electrons need to absorb a DISCRETE amount of energy to
move to a higher energy level (1)
Photons need to have a certain frequency to provide this
energy, because E=hf (1)
interaction is a 1:1 reaction all of the photon's energy is
absorbed (1)
Explain how excitation takes place in a fluorescent tube -
CORRECT ANSWER-Electrons flow through the tube to the applied
PD causing a current to flow (1)
Electrons collide with mercury atoms in the tube (1)
This raises electrons in the mercury atom to a higher energy
level (1)
What is the purpose of coating in a fluorescent tube? - CORRECT
ANSWER-UV/ High energy photons emitted from mercury atoms
when the electrons in the atom de-excite (1)
High energy photons absorbed by the coating (1)
Coating emits photons in the visible spectrum (1)
What happens when annihilation occurs? (2) - CORRECT ANSWER-
particle and an anti-particle collide and cease to exist (1)
Their mass is released as energy in the form of a pair of gamma
photons (1)
How does the strong nuclear force between two nucleons vary
with the separation of the nucleons? (3) - CORRECT ANSWER-
repulsive at < 0.5 fm (1)
attractive from 0.5 to 3 fm (1)