1. How can a neutral item be attracted to a charged object? Devise a test that will tell you whether the ball was neutral or positive. You can use any tools, even something not in your lab kit.

2. Your mother told you never to remove toast from a toaster with a metal knife. Did you listen? Let's say for a moment that you didn't. Which are you more likely to survive, being in parallel with the toaster wires or being in series? Explain.

3. Voltages are always measured between two points. Why?

4. If you wish to store a large amount of energy in a capacitor bank, would you connect capacitors in series or parallel? Explain.

So I know that two particles can be entangled in a quantum way, but is it possible that more than two particles be entangled in a quantum way? Most descriptions provide with two-particles cases, so I wonder. (It's hard to think of three particles entangled in spin, or so.)

How have the abundance of H and He in the universe changed since the big bang? Why or why not?

An isolated parallel-plate capacitor (not connected to a battery) has a charge of Q = 2.4×10−5C. The separation between the plates initially is d = 1.2 mm, and for this separation the capacitance is 3.1×10−11F. Calculate the work that must be done to pull the plates apart until their separation becomes 8.3 mm, if the charge on the plates remains constant. The capacitor plates are in a vacuum.

Express your answer using two significant figures

What is meant by self consistency ? can you give any real life example or example from physics to explain self consistency ?

1. a) The star μ Cephei has an apparent magnitude of +4.73 in the V-band. How many times brighter is its apparent brightness in the V-band than in the B-band if its B-V color index is +2.35?

b) Explain how μ Cephei’s apparent R-band magnitude of +1.98 demon- strates why this star is also known as the Crimson Star.

c) Given that μ Cephei has a luminosity of 3.7 · 105L⊙, estimate this star’s absolute magnitude given its distance of approximately 1800 pc. As- sume that the Sun has an absolute bolometric magnitude of +4.83.

d) μ Cephei also has a surface temperature of 3690 K, estimate its radius. If it were placed inside the Solar System, which planets would be orbitting inside of it?

You are the manager of a 40 head broodmare farm. The mare’s average weight is 1,000 lbs. ➢ You know the mares in early lactation require: 28.3 Mcal DE, 3 lbs Crude protein, 50 g Ca, 34 g P. ➢ You go to the local feed store and purchase a feed that sells of $8.50/50 lb bag. ➢ The nutrient make up of the feed is: 13.5% CP, 0.5% Ca, and 0.44% P. By the fiber content you estimate the DE to be around 1.3 Mcal/lb. ➢ You feed 1% bwt in grass hay (7% CP, 0.8 Mcal DE/lb, 0.4% Ca, 0.2% P) A. How much of the commercial feed must you feed to meet the mares’ requirements (per head, per day)? 21.76 B. If the hay costs $40/ton, what is the monthly cost to feed these 40 mares, in early lactation (grain cost is given above)? a. Hay b. Grain c. Total

Historical background for electricity and magnetism

Explain what each of the following materials are and how they are related to electrostatics or magnetism.

1. Amber:

2. Lodestone:

Explain the following theories.

3. Effluvium Theory:

4. Benjamin Franklin’s One Fluid Theory

5. Dufay’s Two Fluid Theory

6. de Magnete:

7. Gilbert categorized the properties as:

Complete the chart below

A 70.0-kg grindstone is a solid disk 0.530m in diameter. You press an ax down on the rim with a normal force of 160N (Figure 1) . The coefficient of kinetic friction between the blade and the stone is 0.60, and there is a constant friction torque of 6.50N?m between the axle of the stone and its bearings.

A.How much force must be applied tangentially at the end of a crank handle 0.500 m long to bring the stone from rest to 120 rev/min in 8.00s ?

B.After the grindstone attains an angular speed of 120 rev/min, what tangential force at the end of the handle is needed to maintain a constant angular speed of 120 rev/min?

C.How much time does it take the grindstone to come from 120 rev/min to rest if it is acted on by the axle friction alone?

An iron wire has a cross-sectional area of 5.70 ✕ 10−6 m2. Carry out steps (a) through (e) to compute the drift speed of the conduction electrons in the wire.

(a) How many kilograms are there in 1 mole of iron?____ kg/mol

(b) Starting with the density of iron and the result of part (a), compute the molar density of iron (the number of moles of iron per cubic meter). _____mol/m3

(c) Calculate the number density of iron atoms using Avogadro's number. ______atoms/m3

(d) Obtain the number density of conduction electrons given that there are two conduction electrons per iron atom. ______electrons/m3

(e) If the wire carries a current of 20.0 A, calculate the drift speed of conduction electrons. ______m/s

3. Electrical power is transmitted southwards from a hydroelectric plant over a distance of 1000 km via a DC (direct current) transmission line to a consumer. The output is 800 KV at the plant. The transmission line consists of one isolated aluminum strand with 2.0 cm diameter; an identical cable returns back north to the generator. The resistivity of aluminum is 2.20 x 10-8 Ωm. The power fed into the original transmission line at the plant is 1000 MW.

   1. a) Draw a circuit diagram of the problem with power plant, transmission lines and a single resistor as consumer (load). What is the total current that flows out of the plant into the cable?

   2. b) How much power arrives at the consumer, i.e. is dissipated in the load resistor, and what is the voltage one measures between the incoming and outgoing cable at the consumer?

   3. c) The utility company wants to decrease the power losses. They add an identical cable in both directions in parallel to the first one. If you assume the load resistor (consumer) and the output voltage of the power plant stay the same, what would be the new power output of the plant and the fraction of power arriving at the consumer?

   4. d) With now 2 strands in both directions, how would the load resistor have to be set to get the original output power of 1000MW and what fraction of the power would arrive now at the consumer?

   5. e) Briefly discuss if and how the power loss would change if the voltage was increased or decreased, while the output power and resistances of load and transmission lines remain constant.

Time standards are now based on atomic clocks. A promising second standard is based on pulsars, which are rotating neutron stars (highly compact stars consisting only of neutrons). Some rotate at a rate that is highly stable, sending out a radio beacon that sweeps briefly across Earth once with each rotation, like a lighthouse beacon. Suppose a pulsar rotates once every 1.743 206 448 872 75 ± 2 ms, where the trailing ± 2 indicates the uncertainty in the last decimal place (it does not mean ± 2 ms).

How many rotation does the pulsar make in 14.0 days?
(b) How much time does the pulsar take to rotate exactly one million times? (Give your answer to at least 4 decimal places.)

(c) What is the associated uncertainty?

PLEASE CLEARLY ANSWER ALL 3 PARTS:

3. Using at least one of Einstein's "thought-experiments", explain how special relativity addresses how it is possible for observers in two different inertial reference frames to “disagree” about time and distance intervals.

4. Describe how special relativity explains the conditions under which classical mechanics breaks down.(When would you, as an observer begin to notice the effects of time dilation and length contraction?)

5. In the early 20th century, the law of conservation of mass was replaced by the law of conservation of mass-energy. Why was this change needed, and how does E=mc² relate to the special theory of relativity?

Calculate the average energy U(T) and entropy S(T) of a paramagnet with two energy states ±μH in the presence of magnetic field H. Take the limits of high and low temperature and draw schematically the U(T) and S(T) dependences for two different values of H.