Page 28 - Spotlight A+ Physics Form 4.5

Form
5 Physics Chapter 7 Quantum Physics

Paper 1

1. What is the energy for one γ-photon with 6. Figure 1 shows four energy levels for an electron
frequency 10 Hz? C3 in hydrogen atom.
20
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A 10 J C 10 J E
–13
–15
B 10 J D 10 J 4
–12
–14
E 3
2. The energy carried by one blue light photon of
450 nm is C3
E
A 2.21 × 10 J C 6.63 × 10 J 2
–19
–19
B 4.42 × 10 J D 8.84 × 10 J
–19
–19
3. In the Einstein’s photoelectric equation Figure 1 E 1
1
—mv = hf – W, for a metal, the symbol W The possible number of spectral lines produced
2
2
represents the C4 from the transition of energy levels is C4
A minimum energy electron escaped from the A 3
metal. B 6
B minimum energy for ionization of one atom C 9
in the metal. D 12
C minimum photon energy needed to remove 7. The consecutive light photons of wavelength
one photoelectron from the metal surface.
D minimum potential energy for one 590 nm produced by a laser source were
separated at a distance of 0.20 m. What is the
photoelectron to be liberated from the metal power of the laser source in nW?
surface. C4
A 0.1
4. Photoelectron cannot be liberated from clean B 0.3
copper surface by visible light because the C 0.5
C4 D 0.7
A photon energy for visible light is less than 8. Photon is the name given to C2
the work function of copper A one unit of energy quanta.
B threshold frequency of copper is less than B one quantum of electromagnetic radiation.
the frequencies of visible light C one electron emitted from a clean metal
C light intensity of visible light is insufficient to surface.
remove photoelectron from copper surface D one electron liberated from a metal surface
D kinetic energy of the free electron inside by light radiation.
copper is less than photon energy of visible
light 9. Which of the following experiment phenomena
provide evidence for the existence of discrete
5. What is the de Broglie wavelength of a particle energy levels in atoms? C2
with mass m moving at velocity of v ? C1 A Photoelectric effect
h
hm
A —— C —— B Line spectrum from sodium lamps
mv v C Energy distribution of black-body radiation
2πh
h
B ——— D ——– D Visible light spectrum from tungsten
filament lamps
2πmv
mv
CHAP
7
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