Exam 18: Solids and the Theory of Conduction

The resistivity of nichrome at 20ºC is 100 *10^-8 $\Omega$ · m. You have nichrome wire whose diameter is 2.50 mm and need a resistance of 100 $\Omega$ 0. How long would a piece of this wire need to be to provide this resistance?

The graph that shows the current as a function of applied voltage across a pn junction is

If the energy levels are given as E_n = nE₁, by what factor is the total energy of seven fermions greater than seven bosons, both of which are in the ground state?

The probability that an energy state in copper 0.2 eV below the Fermi energy is occupied at T = 300 K is

The crystalline structure known as face-centered-cubic

The probability that an energy state in copper 0.05 eV below the Fermi energy is occupied at T = 300 K is

The crystal structure of a substance can be determined using X-ray diffraction. It can also be determined using neutron scattering. What is the kinetic energy of a neutron that has a wavelength of 0.1 nm?

The Madelung constant is given by the infinite sum $\alpha$ = 6 - 12/2^1/2 + 8/3^1/2 - ... . Which of the following statements is true?

Use the following to answer the next question. -You place sodium and copper in contact. The contact potential you would expect to measure is

When a pnp junction transistor is used as an amplifier, a small signal in the _____ current results in a large signal in the _____ current.

An 8-gauge copper wire (diameter = 3.665 mm) carries a current of 40 A. The drift velocity of the charge carriers is

Use the following to answer the next question. -The Fermi energy in three dimensions at T = 0 is given by E_F = 0.365 eV · nm² (N/V)^2/3 The Fermi energy for aluminum is approximately

The probability that an energy state in magnesium 0.05 eV below the Fermi energy is occupied at T = 300 K is

The graph that shows the current as a function of applied voltage across a tunnel diode is

Use the following to answer the next question. -The Fermi temperature for aluminum is

A pn junction of germanium is connected through a resistor to a variable dc power supply as shown. Which of the following graphs best describes the current I in the circuit as the voltage V of the power supply is varied in the range of approximately -10 V to +10 V?

Use the following to answer the next question. -The graph that represents the Fermi energy distribution function n(E) is

The molecules in a solid

Use the following to answer the next question. -The graph that represents the Fermi factor F is

One of the principal advantages of the transistor over the thermionic triode as a circuit element is that the transistor