We’re going to think about other possible sources for magnetic fields. Recall that the source of magnetic fields in permanent magnets is aligned electron orbits(electrons going in circles all the same direction so the circles are parallel and they are either all traveling clockwise or counter clockwise).

1. Where do electric fields come from? Draw an electric field diagram for each of the two types of source.
2. Pick a spot in one of your field diagrams. How would you determine the electric field there (There’s an equation we used that is closely related to the force on a charge there)? Now, take the same point, but move your source an inch to the right. What is the electric field at that point now?
3. Now, an electron orbit generates a magnetic field. What else does it generate (this is directly related to the answer of question 2)? Is that second thing static (constant) or time-dependent (moving)?
4. Now, why might a circuit generate a magnetic field (Think about questions 2 and 3)? Why?
5. If you wanted to make a wire generate a big magnetic field, how might you design it and why (There are many ways to get to this conclusion)? Congratulations, you have designed an inductor. Place this object in a circuit and it will prevent changes in current.

Transverse waves on a string have wave speed v = 8.00 m/s, amplitude A = 0.0700 m, and wavelength λ = 0.320 m. The waves travel in the -x direction, and at t = 0 the x =0 end of the string has its maximum upward displacement.

1) Find the frequency of these waves.

2) Find the period of these waves.

3) Find the wave number of these waves.

4) Write a wave function describing the wave. Express your answer in terms of x and t. Use π as constant.

5) Find the transverse displacement of a particle at x = 0.360 m at time t = 0.150 s. Express your answer in meters.

6) How much time must elapse from the instant in part E until the particle at x = 0.360 m next has maximum upward displacement? Express your answer in seconds.

a) Calculate, in units of ℏ, the magnitude of the maximum total (orbital+spin) angular momentum for an electron in a hydrogen atom for states with a principal quantum number of 5.

b) An electron initially in a 4p state decays to a lower energy state. Which energy state is forbidden? (pick one): 1s, 2s, 3d, or 2p? Why?

c) What is the total number of electrons that can occupy a subshell for a given amount of orbital angular momentum l? Write an expression in terms of l.

A membrane is fouled with a layer of bacteria (a bioflim). The water permeability of the biofilm is 2 x 10^-12 mol m s^-1 m^-2 atm^-1 and is 21 μm thick. The membrane is 52 μm thick with a water permeability of 1 x 10^-12 mol m s^-1 m^-2 atm^-1. Neglect the convective mass transfer resistance as they are very small.

The partial pressure of water of one side is 200 kPa and 101 kPa on the other.

Calculate the total mass flux of water through the combined membrane and biofilm in mol m^-2 s^-1 (3 SF) eg 1.67E-8.

Conversion 1 atm = 1.01325 x 10⁵ Pa

Useful equations:

  and

In the perfectly elastic case, is there another mathematical expression for the velocities that conserves both momentum and energy? If so, what is it, and why do we neglect this possibility? If not, show this (calculate v1_f and v2_f from v1i and v2_iwhile making sure you do not have any holes in your argument along the way - e.g., do you ever divide by something that could be zero?).

Determine the force (in the lab frame) between two charges moving with the same velocity V. What is the ratio of transverse-to-longitudinal force? Explain what happens to this ratio when the two charges lie on a line parallel to V or perpendicular to V?

A soap film (n = 1.33) is formed in a loop of wire that is mounted vertically is not exactly uniform in thickness because of its weight, but wedge-shaped in cross section. When the film is illuminated with violet light of wavelength 405 nm, one sees that a distance of 2.20 cm separates two bright fringes that are 4 orders apart. By how much does the film differ in thickness over this distance?

For astronomy class, please answer this question clearly, thank you .

Titan’s atmosphere contains a large amount of photosensitive methane. We know because of basic physics and chemistry that there must be a source of methane on Titan that replenishes the atmospheric methane.

a) Describe what astronomers thought might be occurring on Titan before the Cassini/Huygens mission.

b) Describe the findings of the Cassini/Huygens mission that either supported or disproved the original hypotheses.

The potential energy of a magnetic moment in an external magnetic field is U = - ??B. U is smallest when B is parallel to ? and largest when it is antiparallel. Since the magnetic moment of the electron is directed opposite to its spin (because it has a negative charge), the electron’s energy is highest when the spin is parallel to B. The two possible energy states for the electron are the spin up state (m_s = 1212) and the spin down state (m_s = - 1212). Calculate the energy difference ?E (in eV) between these states if the electron is placed in a magnetic field of B = 1.1 T. Assume that n = 10 and l = 0 for the electron.

If these electrons are bombarded with photons that have an energy equal to this energy difference ?E, then the electrons can be excited from the spin down state to the spin up state. This is referred to as a “spin flip” transition and the technique is called Electron Spin Resonance (ESR). Find the wavelength of the photons (in meters) that are needed to excite such spin flip transitions.

What type of electromagnetic wave has this wavelength?

Simple harmonic motion:

A ball dropped from a height of 4.00m makes an elastic collision with the ground in a vacuum chamber. a) What is the difference between the kinetic energy of the ball immediately before the collision and the kinetic energy of the ball immediately after the collision? b) Is the kinetic energy of the ball conserved in its subsequent motion after the collision? c) What is the difference between the momentum of the ball immediately before the collision and the momentum of the ball immediately after the collision? d) Is the total momentum of the system conserved, and if so, what other parts of the system must be included other than the ball? e) Identify an equilibrium point for the entire system. Explain why the motion around this equilibrium point is periodic and determine the period of the motion. f) Is the motion simple harmonic motion? Explain.

Having problem solving this..

Derive the Red Shift in the F.L.R.W. metric and obtain Hubble' s law.

You baked two cakes: one in a light aluminum pan and one in a heavy pyrex pan. Please Match each of the four with either Pyrex or Aluminum as the answer

1. The pan that needs to give up the most heat energy to cool down to room temperature.

2. The pan that gives up the heat energy the fastest

3. The pan most likely to burn your fingers if you try to move it too soon.

4. The pan in which the bottom of the cake is most likely to brown (same temperature oven, same time in oven.)

ANSWER OPTIONS

A .pyrex

B. aluminum

A plane parallel-plate capacitor consists of two identical circular metal plates, each of radius 2.50 cm. the plates separated by 1.00 micrometer. The
charge on the capacitor is 3.50 nC. Values of standard constant can be found in your notes or the textbook.

For these questions, enter only the numerical values. Do not enter the units, which are already given after the blank. Note that the data is given to 3
significant figures. You MUST enter your answers also to 3 significant figures. If you have more decimal places than allowed with a decimal number, use
the scientific notation in the form, eg: x.yzE(-12), or x.yzE(+6). The exponent MUST be a capital E.

Draw a diagram and for each part, show your work and your final answers on your worksheet, which you will submit in Quiz2b.

Find the capacitance: F.

Find the potential difference between the plates:

Find the magnitude of the electric field between the plates:
V/m. Show the diretion of the electric field in the sheet that you will

submit. ^L

Find the total electric potential energy stored in the capacitor:

Find the energy density of the electric field in the capacitor:

Q1

A potential difference of 13 V is found to produce a current of 0.45 A in a 3.1 m length of wire with a uniform radius of 0.36 cm. Find the following values for the wire: (a) the resistance (b) the resistivity