I just wanna ask a simple question, but i need some explanation about it. What is the Physical quantities (Probably Wavelength or something like that) that causes every people has their own unique sound? Not Frequency Right? Because if frequency, people can just adjust their sound to make their frequency same with other people sound.

a) Plot the structure of p-channel MOS-FET (Show semiconductor structure, gate, drain, source
and voltage polarities) and summarize the working principle.
b) Explain what happens if you change drain source voltage polarity.
c) Plot the band diagram, approximate distributions of charge, electric field, and electrostatic potential in
the ideal MOS capacitor in inversion for the p-channel case.

2. The LC circuit’s charge could be described by this second-order differential equation

L d2qdt2+C q=0

where q is the time-dependent charge in the circuit, L is inductance, and C is the capacitance.

The solution to that equation is qt=q0cos(ωt+ ϕ) where q₀ is the maximum charge in the circuit, w is the angular frequency of the circuit, which equals 1L C , and f is the phase angle of the circuit.

a. What does q(t) represent? Yes, I know it means “the charge” but of what? After all, the circuit has the same number of electrons and protons regardless of whether there is current flowing or not, so what does that quantity mean?

b. In order for the initial charge to be zero; that is, q(0) = 0, what does the phase angle f need to be?

The radioisotope ¹⁵O (t_1/2 = 122 s) is used to measure respiratory function. Patients inhale the gas, which is made by irradiating nitrogen gas with deuterons (²H). Consider a cubical cell measuring 1.24 cm on each edge, which holds nitrogen gas at a pressure of 2.25 atm and a temperature of 293 K. One face of the cube is uniformly irradiated with a deuteron beam having a current of 2.05 A. At the chosen deuteron energy, the reaction cross section is 0.21 b. (a) At what rate is ¹⁵O produced in the cell? (b) After an irradiation lasting for 60.0 s, what is the activity of ¹⁵O in the cell?

1. a Calculate the natural log of the capacitor voltage for each time point

b. Add a linear trendline to your graph and display the best fit equation

c. Record the slope from your best-fit equation in step

d. Calculate the capacitor time constant τ using the slope with the equation

e. Calculate the internal DMM resistance R using the following equation:

( I am not sure how to use my data to answer this problem)

Explain the procedure of creating a direction field (by hand) in your own words. Then explain how Euler's method works and why someone uses Euler's method. Your response should be about 250 words.

1. How is magnetism no more than electrostatics combined with special relativity? Explain.

Investigate the use of electron beam lithography to make small structures. Find an example in the literature. Explain its advantages and limitations.

Diffusion is a key element of integrated circuit fabrication. Describe the two basic heat treatments that are used to diffuse impurities into silicon during this fabrication process.

7. Compare the energy needed to move 20 people 10km with 5 cars of 4 people with 3 stops at a speed of 70km / h.

With a bus that stops every 2000m and only reaches a speed of 45 km / h.

Both engines have an efficiency of 30%, the car with 4 people weighs 1.4 tons, the bus 12.5 tons (including 20 people).

c_dA = 0.8m2 for the car and the bus is 3.2m high and 2.5m wide and has an air resistance coefficient of 0.5.

Hobbis et al (Inorg. Chem., 2019, 58 (3), pp 1826–1833) thoroughly examined the properties of a niobium-iron-antimony semiconductor material. Although their reported synthetic procedure was a fairly straightforward stoichiometric melting and subsequent crystallization of the pure elements, they did not observe the predicted behavior of an intrinsic semiconductor. Instead, their compound was found to exhibit characteristics of a very lightly n-doped semiconductor instead. They hypothesize that this is due to the formation of so-called “antiphase domains” during crystallization, where the local pattern of atoms in small regions in the solid is the exact reverse of the rest of the crystal structure. Given the three elements involved, suggest an explanation (using a diagram if you find it helpful) for how this change in atomic pattern gives rise to n-type doping behavior.

Infrared spectroscopy takes advantage of the ability of covalent bonds in a molecule to absorb light of certain energy. To assign particular peaks in an IR spectrum to a certain type of bond, covalent bonds are modeled as springs between two atoms. Hooke’s Law tells us that the energy (U) of the bond is a function of temperature and the distance between the atoms, so U = U(T,x). The change in volume upon stretching a bond is negligible, so the work done on the bond is given by w = F dx.

a. Write out an expression for the differential change in entropy, starting with the first/second laws of thermodynamics and the total derivative of U(T,x). Assume the stretching of a bond through infrared light exposure is reversible.

b. If the process occurs at constant temperature T and Hooke’s Law says that U = ½ kx²  (where k is referred to as the spring constant) and F = 4x, give the expression for DS when stretching a bond from x₁ to x₂.

for each circuit component tested, write a brief analysis of the component. Explain how you know whether it is "ohmic" or not.

Testing Ohms Law

Component 1: Lamp

Component 2: Resistor

Component 3: LED

Component 4: Diode

Please explain why it is ohmic or not

You are investigating two mysterious objects with mass M = 0.7 kg and diameter R = 0.2 m, which are rolling down a slope without slipping. The slope makes an angle θ = 30 ° with the horizontal. The acceleration of gravity for an object in free fall is 9.8 m/s².

(a) Draw a force diagram, showing all the forces on the object.

[2 marks]

(b) You are measuring the time it takes the objects, from rest and without slipping, to roll down the L = 1.00 m long slope, as measured along the slope. Show that the arrival time at the bottom for an object with moment of inertia I = cMR² is

t = 2 ( 1 + c ) L g sin ⁡ θ

[3 marks]

(c) Like a good experimentalist, you are taking a number of repeat measurements. In the following, make sure you quote all answers to an appropriate precision. Your measurements are captured in the following table.

          (i) Find the average times that the two objects take to roll down the slope. Include the associated uncertainties in your result.

[2 marks]

          (ii) Deduce the accelerations of the two objects, with uncertainties. Show your working.

[2 marks]

          (iii) Explain why the two objects roll with different accelerations.

[2 marks]

          (iv) What is your best guess of the geometry of your objects? Provide reasoning for your guess.

[2 marks]