Section 2 - Electromagnetic radiation and Quantum Phenomena
1/11/24
Line Spectra in atoms
In an absorption spectrum, photons are absorbed at different specific
energy levels, so it appears as a black line.
1. 3 possible transitions – 3 to 2, 2 to 1, 3 to 1.
2. 13.6-1.51=12.09eV = 1.93E-18
1.938E-18=hf so f=2.92E+15Hz
λ=c/f = 1.03E-7m = 103nm
3. A) No excitation
B) Colliding electron carries away excess energy.
C) Ionisation with excess energy (1.4eV) carried away by colliding
electron.
Fluorescent tube
, 1. High speed electrons collide with mercury atoms.
2. Mercury atoms are excited. Photons released in UV range.
3. UV photons excite other atoms in coating.
4. Photons released in visible range.
7/11/24
Photoelectric effect
, Work function – the amount of energy required to remove electrons from
the surface of a metal.
1/11/24
Line Spectra in atoms
In an absorption spectrum, photons are absorbed at different specific
energy levels, so it appears as a black line.
1. 3 possible transitions – 3 to 2, 2 to 1, 3 to 1.
2. 13.6-1.51=12.09eV = 1.93E-18
1.938E-18=hf so f=2.92E+15Hz
λ=c/f = 1.03E-7m = 103nm
3. A) No excitation
B) Colliding electron carries away excess energy.
C) Ionisation with excess energy (1.4eV) carried away by colliding
electron.
Fluorescent tube
, 1. High speed electrons collide with mercury atoms.
2. Mercury atoms are excited. Photons released in UV range.
3. UV photons excite other atoms in coating.
4. Photons released in visible range.
7/11/24
Photoelectric effect
, Work function – the amount of energy required to remove electrons from
the surface of a metal.
