Assignment: Solid State Electronics and Materials
1. This problem is about water. It has a mass density of 1 gram/cm3 and one mole of water weighs 18 grams. Temperature is 300K.
a). From the known relative permittivity of water at frequency lower than 5 GHz, find its susceptibility, i.e., its numeral value.
b). Calculate the number of water molecules per cm3 and the size of a molecule assuming that it is a cube.
c). Using the result of problem 3.13(b), calculate the permanent dipole of a water molecule.
d). Permanent dipole, p = 2eδ, where e is the magnitude of electron charge. Calculate δ and compare it with the size of a molecule.
2. This experiment is conducted in fresh water. You shine a green laser beam with power of 15 rnilliwatts at normal incidence on a 5-mm thick BK7 glass plate having index of refraction of 1.517. The glass has an absorption coefficient of α = 1 /cm at green light. Calculate:
a) The amount of laser beam power that reflects back to you.
b) The amount of laser power that enters the front surface of the glass plate.
c) The amount of laser power that gets out of the rear surface of the glass plate.
d) What happens to the light power consumed in the glass? Where does it go?
3. Let us assume that the magnetic dipole produced by an electron revolving at its nucleus with a radius of 0.02nm is the same as the electron spin dipole. Calculate the rate of revolution per minute.
4. Explain how a permanent magnet is used in an electrical generator to produce electricity.
5. Identify 5 products that use soft magnetic materials.
6. Define: yield strength, Young's modulus, and ultimate tensile strength.
7. Design an experiment to measure the Young's modulus of a material without using tensile tester.