Oxygenated hemoglobin absorbs weakly in the red (hence its red color) and strongly in the near infrared, whereas deoxygenated hemoglobin has the opposite absorption. This fact is used in a "pulse oximeter" to measure oxygen saturation in arterial blood. The device clips onto the end of a person's finger and has two light-emitting diodes—a red (632 nm) and an infrared (930 nm)—and a photocell that detects the amount of light transmitted through the finger at each wavelength.

(a) Determine the frequency of each of these light sources.

red Hz

infrared Hz

(b) If 66% of the energy of the red source is absorbed in the blood, by what factor does the amplitude of the electromagnetic wave change? Hint: The intensity of the wave is equal to the average power per unit area as given by I = Emax2 2μ0c = c 2μ0 Bmax2.

A uniform thin rod of length 0.778 m is hung from a horizontal nail passing through a small hole in the rod located 0.057 m from the rod's end. When the rod is set swinging about the nail at small amplitude, what is the period of oscillation?

A 92.0-N uniform, horizontal board 14.0 m long rests on two supports, each 1.00 m from the

end of the board. A 385-N block is placed on the board 3.00 m from one end as shown below.

Find the force exerted on the board by each support.

The energies of the hydrogen atom are quantized by integer number n from 1 to infinity. This number if called the principal quantum number. Find:

a) principal quantum number

b) binding energy

c) orbital radius

d) total enery

e) excitation energy of the fifth state of hydrogen

What are some advantages and disadvantages of thermal oxidation?

A bug of a known mass m stands at a distance d from the axis of a non-uniform spinning disk with radius r and unknown rotational inertia I that is rotating at fi revolutions per second. After the bug walks out to the edge of the disk and stands there, the disk rotates at ff revolutions per second.

a. Determine the rotational inertia of the non-uniform disk.

b. Determine the change of kinetic energy in going from the initial to the final situation for the total bug-disk system.

A car is traveling down the expressway at 31.7 ? with no acceleration. How far has the car? traveled in 3.9 hours? If the speed limit in such expressway is 70mph, should the driver receive a speed ticket?

A car is traveling down the same expressway as in the previous problem, it is traveling at 22.3 7 ?. If it constantly accelerates at a rate of 4.3 ?, in how many minutes is it going to pass the speed limit.

Explain the motion of a rattleback. Do not just describe motion Explain the motion.

Consider a 4-mg raindrop that falls from a cloud at a height of 2 km.

Part a) If we neglect air resistance, what would be the speed of the raindrop when it reaches the ground? Assume that the falling raindrop maintains its shape so that no energy is lost to the deformation of the droplet.

________ m/s

Part b) When the raindrop reaches the ground, it won't kill you or even bruise you because its terminal velocity is just 10 m/s. Calculate the work done by the air resistance on the raindrop. Recall that positive work done on an object/system increases the energy of that object/system. Again, assume that the falling raindrop maintains its shape so that no energy is lost to the deformation of the droplet.

________ Joules

Part c) What percentage of the raindrop's initial mechanical energy was lost to air resistance? (Based on your answers, ask yourself if you think it is reasonable to ignore air resistance when evaluating the fall of a raindrop from the sky.)

________ %

why is GaN has wide band gap compare with Si?

Why does Gravity Exist? Why is any body able to attract another? Where does that energy emerge from? Is there anything like gravitational repulsion?

Derive an expression of the mean free path of a gas molecule assuming a hard sphere collision. Calculate the ratio of the mean free path of CO molecules in a vessel at a pressure P1=10-4 Torr at 300 K to that at a pressure P2=10-9 Torr at the same temperature. (CO molecules d =0.73nm)

What type of measuring device relies on Zeroth’s Law and how does it do this?

The temperature outside is 0 degrees Fahrenheit. What is the temperature in Kelvin?

An isolated system absorbs a heat transfer of 45J and performs 20 J of work. What is the internal energy of the system?

An isolated system contains some amount of internal energy. If 5 J of heat are transferred into the system, but the internal energy remains the same, how much work must be done by the system?

How much work is done by a jet engine that exerts 245 N of force over a distance of 1 km?

A gas maintains a constant pressure of 45 N/m² while being heated. The resulting change in volume is 0.78 m³. What is the work done by the gas?

The same gas in problem 6 had an internal energy of 85 J and a final volume of 2 m³. What is the enthalpy (H) of the gas?

The combustion process inside a jet engine creates 450 J of heat and does 110 J of work spinning a turbine shaft. What is the change in specific enthalpy of the gas?

Through an irreversible process, object A transfers 96 J of heat to object B. The resulting temperature of the system is 456 K. What is the entropy of the system?

For an ideal gas, if the pressure remains the same but the volume is doubled, what would you expect to happen to the temperature? Why?   **Hint: use the equation of state to help justify your answer.

The size of an object parallel to the axis of rotation does not enter into the calculation of its moment of inertia. Why?