Exam 28: Quantum Physics

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. $\Delta$ E $\Delta$ t $\ge$ h/4 $\pi$ .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?

A 15-kg mass,attached to a massless spring whose force constant is 2 500 N/m,has an amplitude of 4 cm.Assuming the energy is quantized,find the quantum number of the system,n,if E_n = nhf.

An electron is sitting on a pinpoint having a diameter of 2.5 $\mu$ m.What is the minimum uncertainty in the speed of the electron?

What is the quantum number n of a particle of mass m confined to a one-dimensional box of length L when its momentum is 4h/L?

The wave function for a particle in a one-dimensional box is $\Psi = A \sin \left( \frac { n \pi x } { L } \right)$ .Which statement is correct?

A photon whose energy is 8.00 *10 ^{- 15} J is scattered off an electron at a 90 $\degree$ angle.What is the wavelength of the scattered wave?

If a rubidium surface is irradiated with blue light of wavelength 450.0 nm,what is the kinetic energy of the electrons emitted? (The work function for rubidium is $\phi$ = 2.09 eV. )

Find the kinetic energy (in terms of Planck's constant)of a baseball (m = 1 kg)confined to a one-dimensional box that is 25 cm wide if the baseball can be treated as a wave in the ground state.

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

Light can exhibit the characteristics of

The average position,or expectation value,of a particle whose wave function $\Psi$ (x)depends only on the value of x,is given by < x > =

Find the uncertainty in the momentum (in kg . m/s)of an electron if the uncertainty in its position is equal to 3.4 *10 ^{- 10} m,the circumference of the first Bohr orbit.

Classically,the concept of "tunneling" is impossible.Why?

What is the energy in eV of a photon of yellow light? $\lambda$ = 500 nm.

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

A particle is in the ground state of a one-dimensional box of length 1.0 m.What is the minimum value of its momentum (in kg .m/s)?

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

A helium-neon laser emits red light having a wavelength of 6.4 *10 ^{- 7} m and a power of 0.5 mW.How many photons are emitted each second?

A physically reasonable wave function, $\Psi$ (x),for a one-dimensional system must

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