# Philosophy 2032F/G Study Guide - Final Guide: Bohr Model, Hidden Variable Theory, Measurement Problem

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Published on 18 Apr 2013

Department

Philosophy

Course

Philosophy 2032F/G

Professor

1. Geodistics in special relativity

Timelike geodesic: The timelike curve connecting two events of greatest proper

time.

2. Galileos principle of objects to free fall and how it is related to special relativity?

Galileo, who articulated the first "relativity principle" in the seventeenth century.

In generating his relativity principle, Galileo removed the distinction between

stationary and moving observers, arguing that people on earth cannot tell if they

are really at rest or if they are moving with the rotation of the earth each day. To

demonstrate this, Galileo used the example of a cannonball falling from the top of

a ship's mast. He noted that the cannonball will land at the base of the mast

whether the ship is moving steadily through the ocean, or whether it is at rest in a

dock. Even if they observe the falling ball, people on the ship cannot tell if they

are really at rest or if they are moving with the ship. They cannot distinguish their

state of rest from the ship's state by observing motion that takes place within the

"reference frame" of the ship. In other words, a person at rest on the deck of a ship

cannot determine whether the ship is at rest or moving at a steady speed through

the ocean by observing actions that happen on the ship itself. That person must

observe the ship relative to its surrounding environment in order to make such a

determination.

3. Revive statistical mechanics that went into the background work of quantum

mechanics.

Ideal gas Law, Diffusion, Browlie

4. Why Einstein used quanta?

Einstein used quanta because he concluded that light and gas obeyed the same

laws at high frequencies. Photoelectric effect- this effect showed that high

frequency light was needed to knock of cathodes. This showed that light behaved

in a different wave. When low frequency light hit the wall it wouldn’t have

enough quanta energy but when high frequency did it would.

5. You need to know qualitatively how time dialation works?

Since speed is equal to distance over time and light is a constant there needs to be

altercations to the equation when working with the speed of light. For example if

the distance increase the time needs to decreae to make up for this. And if the

time increases then to the length has to decrease to make up for this to. Can use

hyperplanes of simultaneity to judge telative time dilations. Twin paradox etc.

Special relativity: the laws of physics are the same in all inertial references, and

the speed of light is constant.

6. How Schawrazchild spacetime works and what can it be used for?

It is a universe where it looks like Minoskwi spacetime has you get closer ot

infinity. It has a central point in space where curvature around it is symmetrical.

Good spacetime around the sun ( assume no sun doesn’t rotate or electrical

charge)

Einstein had two problems with this spacetimes. First from the empirical date they

had at that time the universe was filled with equal distribution of stars. Second he

likes a fixed spacetimes depending on matter distribution based on General

relativity. Einstein didn’t like the arbitrariness of infinity when you reached closer

to infinity as you predicted a curvature without knowing the mass distribution.

7. Need to know the properties of the Einstein universe and what it can be used for?

He abolished spatial infinity. He did this by introduction a new constant in his

equations. It contains a uniform mass distribution so that matter is at rest and

geometry of space slices are unchanging with time. Overall is it s 5none geometry

with no infinity and space curving back onto itself. The space time is

Homogeneous with the same spatial curvature in all directions. It is spatially

isotropic, meaning it is the same in every direction of spatial direction. Einstein

added a constant to his equation in order to supply the missing curvature needed

for his universe:

Summed of Space curvate plus lamba= matter density

De sitter arugued that this lamba actually expanded the universe without matter

despite its intentions.

The lamba is a repulsive force that cancels out the gravitational force that would

be present in his spacetime so that his spacetime would not collapse.

Lamda was changed to show that spacetime=-lambda, it behaves like an odd

matter that expands the matter in the universe.

Time Travel Universe (Einstein Universe)- If you take the cylinder and have the

one dimension time on the surface you can go forward and meet youself in the

future. Grandfather Paradox. The grandfathers assasion would not occur. (global

constraints).

8. What do different type of geodesic deviation say about different kind of

curvature?

Spherical Geometry- Positive Curvature- 5NONE- Lines connect back to

themselves. Triangle- Sum More then 180 degrees. Perpindiculars

Converge(diverge slower then expected)

Euclidean Geometry- Flat- Infinite length- 180- perpendicular netiher converge or

diverge

Hyperbolic Geomtetry- Negative Curvature- 5MORE- Less then 180-

Perpindicualrs Diverge. (converge slower then expected)

9. What is superposition? And how do you interpret them?

You can add up waves. In a superposition the wave is concentrated in one place.

It shows that a spatially localized particle has a whole set of momentums because

of superposition to get that localized wave packet.

10. In principle what it would be like to pass through the even horizon of the black

hole?

You would be hit by tidal forces and spagettified until you hit the singularity. The

time cones would tilt toward singularity as you got closer to the event horizion,

where inside it would completely tilt so your only possible future would be

towards the singularity. You would not feel going through the event horizon but

an observes would only see you frozen at the even horizon but never actually pass

through it.

11. What the measurement problem and why is it a problem?

A quantum system can evolve in time in only two ways. One is Schroedingers in

which wave of a system propogates in a familiar manner of waves. The other way

is through collapsing which happens when we measure it. The lack of precise data

to which evoluation will arise has created a constulation puzzle. The best known

example of this schodingers cat. Responses to it: Accept the standard account,

hidden variable theory, new dynamics, no collapse theory

12. The difference between Newtonian gravitational theory, special relativity, and

general relativity and also how they are related?

13. Rutherford model of the atom

Charged positive nucleus with negatively charged electrons that go around it.

Energy gained move further away from nucleues and when come back release

energy as emission. First problem as it came down it’d pass through continuous

range of frequencies and therefore emit a continuous range so there was no way to

control it. Second nothing stops this emission and the electron will emit until it

reaches the nucleus and crashes.

14. How electrons orbit around a nucleus

Depends which model .

15. Bohr model of the atom

Stable orbits around the nucleus that electrons could orbit without losing energy.

Energy that allows it to jump has to be equal to the energy needed to go from one

orbit to the other. The angular momentum of orbiting electrons came in full

multiples.

16. Relation between the Brownian motion and the atomic hypothesis

Small particle are pushed about my smaller atoms. Sometimes one side pushes the

other. This movement is completely random. Follows a certain law of probability.