C.9 Does energy need to be continually supplied to maintain a population inversion? Explain your answer.Yes NoSection Problems
Section 2 - Balmer series
2.1 What wavelength light is emitted from a hydrogen atom when the electron transitions from a state where n = 4 to one where
n = 2?
nm
2.2 If a visible photon with wavelength 434 nm is emitted from an atom in a hydrogen gas lamp, what energy state was the atom
in before the photon was emitted? That is, what was the number n for that state?Section 3 - Photons
3.1 Visible light consists of photons having energies that range from 2.8×10í^19 J to 5.0×10í^19 J. What is the range of photon
frequencies in visible light?
Hz up to Hz
3.2 Given the information in the previous problem, what is the range of photon wavelengths in visible light?
lowest wavelength: m
highest wavelength: m
3.3 Gamma ray bursts come from tremendous explosions in faraway galaxies. These bursts are thought to be produced during
the end stages of the lives of massive stars, and give off more energy than any other observed astrophysical phenomenon. A
gamma photon in such a burst could have a frequency of 10^21 Hz. A typical visible photon has a wavelength of 550 nm.
Roughly how many times more energetic is this gamma photon than a typical visible photon?
i. 10
ii. 1000
iii. 1000000
iv. 1000000000Section 5 - Photoelectric effect
5.1 Electrons can be ejected from a clean silver surface using light with wavelengths as large as 262 nm. What is the work
function for silver?
eV
5.2 Potassium has a work function of 2.21 eV. What is the maximum kinetic energy of electrons escaping from a sample of
potassium if photons of frequency 6.00×10^14 Hz strike it?
J
5.3 In a demonstration of the photoelectric effect, electrons leave a calcium surface with velocities as great as 2.0% of the speed
of light. If the work function for calcium is 3.2 eV, what is the wavelength of the incident radiation? Relativistic effects may be
neglected.
nm
5.4 Platinum has a work function of 6.4 eV. Radiation with wavelength 150 nm and intensity 1.3 W/m^2 is directed at a platinum
surface. (a) Find the maximum kinetic energy of the ejected electrons. (b) If 1.0% of the photons striking a 1.0 cm^2 area of
platinum eject electrons, how many electrons are emitted per second from that part of the surface?
(a) J
(b) electrons per secondSection 8 - Bohr atom
8.1 If a 12.1 eV photon was absorbed by a hydrogen atom initially in its ground state, which then emits 2 photons, what are the
emitted photon wavelengths?shorter wavelength: nm
longer wavelength: nm(^686) Copyright 2000-2007 Kinetic Books Co. Chapter 36 Problems