Choose the best answer.

1		When light is directed at a metal surface, the energies of the emitted electrons ______________.
			A)	vary with the intensity of the light
			B)	vary with the frequency of the light
			C)	vary with the speed of the light
			D)	are random
2		In a vacuum, all photons have the same ________________.
			A)	frequency
			B)	wavelength
			C)	energy
			D)	speed
3		The mass of a photon __________________.
			A)	is 0
			B)	is the same as that of an electron
			C)	depends on its frequency
			D)	depends on its energy
4		When the speed of the electrons that strike a metal surface is increased, the result is an increase in __________________.
			A)	the number of x-rays emitted
			B)	the frequency of the x-rays emitted
			C)	the speed of the x-rays emitted
			D)	the size of the x-rays emitted
5		A phenomenon that cannot be understood with the help of the quantum theory of light is __________________.
			A)	the photoelectric effect
			B)	x-ray production
			C)	the spectrum of an element
			D)	interference of light
6		According to the theories of modern physics, light _______________.
			A)	is exclusively a wave phenomenon
			B)	is exclusively a particle phenomenon
			C)	combines wave and particle properties
			D)	has neither wave nor particle properties
7		According to the theories of modern physics __________________.
			A)	only stationary particles exhibit wave behavior
			B)	only moving particles exhibit wave behavior
			C)	only charged particles exhibit wave behavior
			D)	all particles exhibit wave behavior
8		The description of a moving body in terms of matter waves is legitimate because ___________________.
			A)	it is based upon common sense
			B)	matter waves have actually been seen
			C)	the analogy with electromagnetic waves is plausible
			D)	theory and experiment agree
9		According to the uncertainty principle, it is impossible to precisely determine at the same time a particle's ____________________.
			A)	position and charge
			B)	position and momentum
			C)	momentum and energy
			D)	charge and mass
10		The sun's spectrum consists of a bright background crossed by dark lines. This suggests that the sun ___________________.
			A)	is a hot object surrounded by a hot atmosphere
			B)	is a hot object surrounded by a cool atmosphere
			C)	is a cool object surrounded by a hot atmosphere
			D)	is a cool object surrounded by a cool atmosphere
11		An electron can revolve in an orbit around an atomic nucleus without radiating energy provided that the orbit ________________.
			A)	is far enough away from the nucleus
			B)	is less than a de Broglie wavelength in circumference
			C)	is a whole number of de Broglie wavelengths in circumference
			D)	is a perfect circle
12		A hydrogen atom is said to be in its ground state when its electron ____________________.
			A)	is at rest
			B)	is inside the nucleus
			C)	is in its lower energy level
			D)	has escaped from the atom
13		An atom emits a photon when one of its orbital electrons __________________.
			A)	jumps from a higher to a lower energy level
			B)	jumps from a lower to a higher energy level
			C)	is removed by the photoelectric effect
			D)	is struck by an x-ray
14		When an atom absorbs a photon of light, which one or more of the following can happen?
			A)	an electron shifts to a state of smaller quantum number
			B)	an electron shifts to a state of higher quantum number
			C)	an electron leaves the atom
			D)	b and C.
15		Which of the following types of radiation is not emitted by the electronic structures of atoms?
			A)	ultraviolet light
			B)	visible light
			C)	x-rays
			D)	gamma rays
16		The operation of the laser is based upon _________________.
			A)	the uncertainly principle
			B)	the interference of de Broglie waves
			C)	stimulated emission of radiation
			D)	stimulated absorption of radiation
17		Which of the following properties is not characteristic of the light waves from a laser?
			A)	The waves all have the same frequency
			B)	The waves are all in step with one another
			C)	The waves form a narrow beam
			D)	The waves have higher photon energies than light waves of the same frequency from an ordinary source
18		The quantum-mechanical theory of the atom is ________________.
			A)	based upon a mechanical model of the atom
			B)	a theory that restricts itself to physical quantities that can be measured directly
			C)	less accurate than the Bohr theory of the atom
			D)	impossible to reconcile with Newton's laws of motion
19		A quantum number is not associated with an atomic electron's ___________________.
			A)	mass
			B)	energy
			C)	spin
			D)	orbital angular momentum
20		According to the exclusion principle, no two electrons in an atom can have the same ____________________.
			A)	spin direction
			B)	speed
			C)	orbit
			D)	set of quantum numbers