HSC Physics Marathon 2016 (1 Viewer)

[Nailgun]

How come lol?
Just point your thumb in whatever direction the current is, and your fingers in whatever direction the external field is in

 

[Nailgun]

Explain how the results of the Michelson and Morley's experiment can be used to support Einstein's assertion that the speed of light is constant. [3]

- In the Michelson-Morley experiment, a beam of light was transmitted towards a half silvered mirror and split at 90 degrees, with each respective beam being reflected back towards the half silvered mirror by 2 mirrors placed equidistant from the half-silver mirrors in the path of the beams. (probs would diagram this) When the beams recombined, Michelson-Morley expected that one of the beams would be slightly faster than the other, and so would form an interference pattern which could be viewed and recorded on an interferometer placed in the path of the recombined beam. The entire apparatus what shifted 90 degrees (it was floating on mercury) and the interference pattern was expected to change, and by analyzing this, they could calculate the speed of Earth relative to the aether.


-However when the experiment was conducted, no change in interference pattern occurred when the apparatus was rotated. This gave the experiment a 'null result', and this result can be explained, and hence supports by Einstein's assertion regarding the constancy of the speed of light. If the speed of light remained constant, then it follows that no change in interference patter would occur, agreeing with the results of the Michelson-Morley experiment, and hence supporting Einstein's assertion regarding the constancy of the speed of light


-Einstein asserted in his theory of special relativity that the speed of light remained constant in a medium (3 x 10^8m/s in a vacuum). This assertion explains, and hence is supported by the null result of the Michelson-Morley experiment as the experiment was based on the premise that light would travel faster than c, when being transmitted through an aether 'moving' relative to the earth in the same direction, and slower when travelling through an aether moving in the opposite direction. The lack of change of the interference pattern implies that this did not occur; that is that the speed of light remained constant and did not vary, which supports Einstein's assertion of the constancy of the speed of light and hence it can be seen that the null result of the Michelson Morley experiment supported Einstein's assertion of the constancy of the speed of light.

 

[leehuan]

- In the Michelson-Morley experiment, a beam of light was transmitted towards a half silvered mirror and split at 90 degrees, with each respective beam being reflected back towards the half silvered mirror by 2 mirrors placed equidistant from the half-silver mirrors in the path of the beams. (probs would diagram this) When the beams recombined, Michelson-Morley expected that one of the beams would be slightly faster than the other, and so would form an interference pattern which could be viewed and recorded on an interferometer placed in the path of the recombined beam. The entire apparatus what shifted 90 degrees (it was floating on mercury) and the interference pattern was expected to change, and by analyzing this, they could calculate the speed of Earth relative to the aether.


-However when the experiment was conducted, no change in interference pattern occurred when the apparatus was rotated. This gave the experiment a 'null result', and this result can be explained, and hence supports by Einstein's assertion regarding the constancy of the speed of light


-Einstein asserted in his theory of special relativity that the speed of light remained constant in a medium (3 x 10^8m/s in a vacuum). This assertion explains, and hence is supported by the null result of the Michelson-Morley experiment as the experiment was based on the premise that light would travel faster than c, when being transmitted through an aether 'moving' relative to the earth in the same direction, and slower when travelling through an aether moving in the opposite direction. The lack of change of the interference pattern implies that this did not occur; that is that the speed of light remained constant and did not vary, which supports Einstein's assertion of the constancy of the speed of light and hence it can be seen that the null result of the Michelson Morley experiment supported Einstein's assertion of the constancy of the speed of light.

You need to specifically mention the aether wind as well as explain it for this kind of question

 

[Nailgun]

You need to specifically mention the aether wind as well as explain it for this kind of question

But I thought I did (albeit in directly)
"transmitted through an aether 'moving' relative to the earth "

 

[leehuan]

But I thought I did (albeit in directly)
"transmitted through an aether 'moving' relative to the earth "

That was the beginning of an explanation

 

[leehuan]

We're talking about science here. You WANT to be explicit

 

[Nailgun]

That was the beginning of an explanation

fair enough lol
fixed it?


- In the Michelson-Morley experiment, a beam of light was transmitted towards a half silvered mirror and split at 90 degrees, with each respective beam being reflected back towards the half silvered mirror by 2 mirrors placed equidistant from the half-silver mirrors in the path of the beams. (probs would diagram this) When the beams recombined, Michelson-Morley expected that one of the beams would be slightly faster than the other, and so would form an interference pattern which could be viewed and recorded on an interferometer placed in the path of the recombined beam. The entire apparatus what shifted 90 degrees (it was floating on mercury) and the interference pattern was expected to change, and by analyzing this, they could calculate the speed of Earth relative to the aether.


-However when the experiment was conducted, no change in interference pattern occurred when the apparatus was rotated. This gave the experiment a 'null result', and this result can be explained, and hence supports by Einstein's assertion regarding the constancy of the speed of light. If the speed of light remained constant, then it follows that no change in interference patter would occur, agreeing with the results of the Michelson-Morley experiment, and hence supporting Einstein's assertion regarding the constancy of the speed of light


-Einstein asserted in his theory of special relativity that the speed of light remained constant in a medium (3 x 10^8m/s in a vacuum). This assertion explains, and hence is supported by the null result of the Michelson-Morley experiment as the experiment was based on the premise that light would travel faster than c, when being transmitted through an aether 'moving' relative to the earth in the same direction, and slower when travelling through an aether moving in the opposite direction. As the earth travels through space at a certain speed v, the aether (which as an abosulte frame of reference was still) would appear to travel at -v when observed from the frame of reference of the earth, hence the phenomena of aether wind, aether that appeared to move. The light traveling with the 'aether wind' would be travelling faster than light travelling against it, and so the change in angles as the apparatus was rotated would affect the respective velocities of the beams, leading to a change in interference pattern. The lack of change of the interference pattern implies that this did not occur; that is that the speed of light remained constant and did not vary, which supports Einstein's assertion of the constancy of the speed of light and hence it can be seen that the null result of the Michelson Morley experiment supported Einstein's assertion of the constancy of the speed of light.

 

[leehuan]

Yep, literally all you had to do cause the info was spot on.

 

[turntaker]

Someone prove the aether theory pls.

 

[Nailgun]

Someone prove the aether theory pls.

Robert B. Laughlin, Nobel Laureate in Physics, endowed chair in physics, Stanford University, had this to say about ether in contemporary theoretical physics:

It is ironic that Einstein's most creative work, the general theory of relativity, should boil down to conceptualizing space as a medium when his original premise [in special relativity] was that no such medium existed [..] The word 'ether' has extremely negative connotations in theoretical physics because of its past association with opposition to relativity. This is unfortunate because, stripped of these connotations, it rather nicely captures the way most physicists actually think about the vacuum. . . . Relativity actually says nothing about the existence or nonexistence of matter pervading the universe, only that any such matter must have relativistic symmetry. [..] It turns out that such matter exists. About the time relativity was becoming accepted, studies of radioactivity began showing that the empty vacuum of space had spectroscopic structure similar to that of ordinary quantum solids and fluids. Subsequent studies with large particle accelerators have now led us to understand that space is more like a piece of window glass than ideal Newtonian emptiness. It is filled with 'stuff' that is normally transparent but can be made visible by hitting it sufficiently hard to knock out a part. The modern concept of the vacuum of space, confirmed every day by experiment, is a relativistic ether. But we do not call it this because it is taboo.

There you go, straight from wikipedia lol

 

[turntaker]

Thanks

 

[RachelGreen]

Since we're talking about the aether:
NEXT QUESTION
"The Michelson-Morley interferometer experiment of 1887 was a poor experiment and was doomed to fail. Actually, its only value to Physics is as an example of what failure looks like."
Assess this statement, including reference to the method employed by Michelson and Morley. [6]

 

[leehuan]

Since we're talking about the aether:
NEXT QUESTION
"The Michelson-Morley interferometer experiment of 1887 was a poor experiment and was doomed to fail. Actually, its only value to Physics is as an example of what failure looks like."
Assess this statement, including reference to the method employed by Michelson and Morley. [6]

Whilst the question is legitimate, what it actually means, I must say, is quite horrific...

 

[Nailgun]

Since we're talking about the aether:
NEXT QUESTION
"The Michelson-Morley interferometer experiment of 1887 was a poor experiment and was doomed to fail. Actually, its only value to Physics is as an example of what failure looks like."
Assess this statement, including reference to the method employed by Michelson and Morley. [6]

lelel we had a question like this in our topic test for space, although it was worded a lot less passive-agressively lol

 

[internalsarekey]

NEW QUESTION

Account for Lenz's Law in terms of conservation of energy (2)

 

[Drsoccerball]

NEW QUESTION

Account for Lenz's Law in terms of conservation of energy (2)

Lenz's Law states that if there is a change in magnetic flux, a magnetic field/ current will be induced to counteract the change. This means that the speed of a magnet passing through a current carrying conductor will essentially slow down. Let's suppose that the opposite was true. If the magnet approached the current carrying conductor it will accelerate producing energy from nothing (as there is extra speed being obtained). Now by observing Faraday's experiment's we know that when a m field approaches a current carrying conductor there is a change in magnetic flux. Therefore the only options for the experiment is that it either violates the Law of conservation of energy OR it follows Lenz's law.

 

[leehuan]

NEW QUESTION

Account for Lenz's Law in terms of conservation of energy (2)

This is a 3 mark value question. Not 2. A full response of this questions requires defining Lenz's law AND CLEARLY accounting for BOTH cases; that of which defies and which follows.

 

[Drsoccerball]

This is a 3 mark value question. Not 2. A full response of this questions requires defining Lenz's law AND CLEARLY accounting for BOTH cases; that of which defies and which follows.

I thought it was strange when I wrote up my answer ...

One day Integrand decided to go to UNSW orientation day. Upon driving there, he realised that his phone was low on battery. He plugged his phone into the car's charger(The cigarette hole) and noticed something strange. He looked at the battery icon of his phone and noticed that the charge kept turning off and on. Explain why this is bad for Integrand's phone.

 

[internalsarekey]

This is a 3 mark value question. Not 2. A full response of this questions requires defining Lenz's law AND CLEARLY accounting for BOTH cases; that of which defies and which follows.

true

 

[Nailgun]

I thought it was strange when I wrote up my answer ...

One day Integrand decided to go to UNSW orientation day. Upon driving there, he realised that his phone was low on battery. He plugged his phone into the car's charger(The cigarette hole) and noticed something strange. He looked at the battery icon of his phone and noticed that the charge kept turning off and on. Explain why this is bad for Integrand's phone.

According to Faraday's Law a change in magnetic flux will induce emf as according to the formula emf = (ceebs latexing formula). As current does not reach maximum instantaneously, there is a brief building up period. According to the relationship B = kI/d, current is proportional to B, and hence as the current builds up (therefore changes) similarly there is a change in magnetic flux inducing emf on the phone. As the build up interval is very small, the change in magnetic flux would be very high and hence the repeated emf induced on the phone would be very high, which could lead to damage of the phone's internal components. This will occur both when the charge is turning on and when it is turning off, meaning that the emf is being repeatedly applied to the phone, potentially causing damage to the internal components.