The Photon Model Questions
Electronvolt Questions
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Electrons are accelerated in a discharge tube by a pd of 12 kV.
a State the kinetic energy gained by the electrons in eV.
b Calculate the kinetic energy gained by the electrons in joules.
(1 mark)
(1 mark)
The electrons hitting a screen have been accelerated through a vacuum tube and have each
gained a kinetic energy of 6.4 keV. Calculate:
a the accelerating pd
b the kinetic energy gained by the electrons in joules.
(1 mark)
(1 mark)
A scientist requires a beam of electrons with energy 5.0  10–16 J. Calculate the accelerating
pd required.
(1 mark)
Energy of a Photon Questions
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Calculate the energy of a photon of red light with frequency 4.3  1014 Hz in:
a joules
b electronvolts.
(1 mark)
(1 mark)
Calculate the energy of a photon of violet light with wavelength 3.5  10–7 m in:
a joules
b electronvolts.
(1 mark)
(1 mark)
Calculate the energy of a photon of yellow light of wavelength 590 nm in:
a J
b eV
(1 mark)
(1 mark)
A photon has energy 4.6  10–19 J. Calculate:
a its frequency
b its wavelength.
(1 mark)
(1 mark)
A photon has energy 10.21 eV. Calculate:
a its frequency
b its wavelength.
(2 marks)
(1 mark)
In a blue LED, a photon is emitted when an electron fills a positive hole (a gap left by a
missing electron). The wavelength of the photon is 470 nm. Calculate the energy, in eV,
transferred from the electron to the photon.
(2 marks)
10 An electron is accelerated through a pd of 15 kV and strikes a metal target. If all the energy
is transferred to a photon of electromagnetic radiation, deduce the wavelength of the
photon emitted.
(2 marks)
11 X-rays are required with a wavelength of 0.10 nm. Calculate the accelerating pd required for
an X-ray tube to produce rays with a minimum wavelength of 0.10 nm.
(2 marks)
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