Download July 22 - Physics

University of Akron
July 22, 2008
Physics 262: Personal Response System Questions
(A) A laser emits photons of a single wavelength. Assume there
are two lasers of the same power (say, 5 watts). One emits
light at wavelength 400 nm, the other at 800 nm. Which laser
emits more photons per second?
1. 400 nm laser 2. 800 nm laser
3. The same for both lasers
(B) In Compton scattering, a photon scatters off a stationary
electron. The wavelength of the scattered light is in general
_________ the wavelength of the incident light.
1. longer than
2. the same as
3. shorter than
Which of the following transitions in a hydrogen atom result in the
emission of light with the (C) longest and (D) shortest wavelength.
1.
n  2  n 1
3.
n n  2
2.
4.
n 3n  2
n  4n 3
(E) An emission spectrum for hydrogen can be obtained by
analyzing the light from hot hydrogen gas, in which many of the
H atoms are in excited states (assume that all the states n = 1,
2, 3, …  are occupied). An absorption spectrum can be
obtained by passing light from a broadband incandescent
source through hydrogen gas. If the absorption spectrum is
obtained at room temperature, when all atoms are in the ground
state, the absorption spectrum will
1. be identical to the emission spectrum.
2. contain some, but not all, of the lines appearing in the
emission spectrum.
3. contain all the lines seen in the emission spectrum, plus
additional lines.
4. look nothing like the emission spectrum.
(F) Consider the element
each nucleus?
1.
2.
3.
4.
207
82
Pb . How many neutrons are there in
82
125
207
289
22
(G) If a 11 Na nucleus absorbs a beta particle, the resulting nucleus
will be
1.
22
10 Ne
2.
23
12 Mg
3.
23
11 Na
4.
22
11 Na