Exam 40: Introduction to Quantum Physics

Because of Heisenberg's Uncertainty Principle,the velocity of a particle is known least precisely when the length of the wave packet representing the particle is

A wave packet can represent a quantum particle because

The number of photons per second passing a plane perpendicular to a collimated monochromatic (one frequency)beam of light transporting power P is directly proportional to

The light intensity incident on a metallic surface produces photoelectrons with a maximum kinetic energy of 2 eV.The light intensity is doubled.Determine the maximum kinetic energy of the photoelectrons (in eV).

The experimental observation(s)below that require(s)a quantum explanation for the photoelectric effect

Because the factor h on the right side of the Heisenberg uncertainty principle has units of Joule-seconds,it suggests that the energy of a system also has uncertainty.The uncertainty in energy depends on the length of the time interval during which a system exists.ΔEΔt ≥ h/4π.Suppose an unstable mass is produced during a high-energy collision such that the uncertainty in its mass is m_e/100.(m_e = 9.11 × 10−³¹ kg. )How long will this particle exist?

Photoelectrons are ejected when monochromatic light shines on a freshly-prepared (oxide-free)sodium surface.In order to obtain the maximum increase in the number of electrons ejected per second,the experimenter needs to

Assume we can determine the position of a particle within an uncertainty of 0.5 nm.What will be the resulting uncertainty in the particle's momentum (in kg ⋅ m/s)?

What is the shortest x-ray wavelength that can be produced in a 12-keV x-ray machine?

How much energy is in a 63 kHz photon of AM-radiation?

A pendulum located where Has a 0.500 kg bob and a 4.00 Hz oscillation frequency.If it is released from a point 0.150 m above the lowest point it reaches,the number of quanta in this oscillation is

How much energy is in an 89.7 MHz photon of FM-radiation?

An atomic level has a lifetime,τ,of )What is the linewidth, ,of this level?

In electron diffraction,an electron moving at speed v << c acts like

Microscopes are inherently limited by the wavelength of the light used.How much smaller (in order of magnitude)can we "see" using an electron microscope whose electrons have been accelerated through a potential difference of 50000 V than using red light (500 nm)?

A stopping potential of 3.2 V is needed for radiation whose wavelength is 200 nm.What is the work function (in eV)of the material?

Assume electrons are accelerated through a potential difference of 25000 V inside a TV picture tube.What is the minimum wavelength that could be produced when the electrons strike the phosphor? (1 Å = 10−¹⁰ m)

When a photon collides with a free electron at rest and the direction of motion of the photon changes,

A neutron has a mass of 1.67 × 10−²⁷ kg.Its de Broglie wavelength is 1.4 × 10−¹⁰ m.What is its kinetic energy (in eV)?

Your temperature is 98.6°F.Assuming your skin is a perfect radiator (ε = 1),determine the wavelength corresponding to the largest intensity (in μm).