Questions from Modern Physics

Q: You’ve entered a survival contest that will include building a crude telescope

You’ve entered a survival contest that will include building a crude telescope. You are given a large box of lenses. Which two lenses do you pick? How do you quickly identify them?

Q: Light from an ideal spherical blackbody 15.0 cm in diameter

Light from an ideal spherical blackbody 15.0 cm in diameter is analyzed by using a diffraction grating that has 3850 lines/cm. When you shine this light through the grating, you observe that the peak-...

Q: What must be the temperature of an ideal blackbody so that photons

What must be the temperature of an ideal blackbody so that photons of its radiated light having the peak-intensity wavelength can excite the electron in the Bohr-model hydrogen atom from the ground le...

Q: A large cavity that has a very small hole and is maintained

A large cavity that has a very small hole and is maintained at a temperature T is a good approximation to an ideal radiator or blackbody. Radiation can pass into or out of the cavity only through the...

Q: a. What is the energy of a photon that has wavelength

a. What is the energy of a photon that has wavelength 0.10 µm? b. Through approximately what potential difference must electrons be accelerated so that they will exhibit wave nature in passing throug...

Q: Electrons go through a single slit 300 nm wide and strike a

Electrons go through a single slit 300 nm wide and strike a screen 24.0 cm away. At angles of ±20.0° from the center of the diffraction pattern, no electrons hit the screen, but electrons hit at all p...

Q: A beam of electrons is accelerated from rest and then passes through

A beam of electrons is accelerated from rest and then passes through a pair of identical thin slits that are 1.25 nm apart. You observe that the first double-slit interference dark fringe occurs at ±1...

Q: Coherent light is passed through two narrow slits whose separation is 20

Coherent light is passed through two narrow slits whose separation is 20.0 µm. The second-order bright fringe in the interference pattern is located at an angle of 0.0300 rad. If electrons are used in...

Q: An electron beam and a photon beam pass through identical slits.

An electron beam and a photon beam pass through identical slits. On a distant screen, the first dark fringe occurs at the same angle for both of the beams. The electron speeds are much slower than tha...

Q: a. A particle with mass m has kinetic energy equal to

a. A particle with mass m has kinetic energy equal to three times its rest energy. What is the de Broglie wavelength of this particle? (Hint: You must use the relativistic expressions for momentum and...