A coiled coil is a structural motif in proteins in which 2–7 alpha-helices are coiled together like the strands of a rope. (Dimers and trimers are the most common types.) Many coiled coil-type proteins are involved in important biological functions, such as the regulation of gene expression — e.g., transcription factors. Notable examples are the oncoproteins c-Fos and c-jun, as well as the muscle protein tropomyosin.
My answer is (B) but the answer key is (A).
My working:
$$\varepsilon=-\frac{d\phi}{dt}$$
$$=-AB\frac{cos\omega t}{dt}$$
$$=AB\omega \sin \omega t$$
Why the answer is zero? I thought the flux will be zero, not the emf.
Thanks
I use FLHR and the plan diagram. This suggests that the left hand side of the coil is going down. I have added annotations to this, which agree with the mark scheme which then goes onto suggest that the coil turns clockwise. To me though this would make it go anti clockwise.
So... what am I...
Hi
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Hello!
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Maybe a not well thought out question:
https://cdn.automationdirect.com/static/specs/78relays.pdf
781-1C-24A Relay is listed as having ##177 \Omega## Coil Resistance. I'm assuming that figure will give the Real Power dissipated by the coil (entire relay circuitry) for some current ##I##, or...
I want to ask about part c (iii). This is what I did:
max e.m.f produced = NBAω = 32 x 0.074 x 4.8 x 10-2 x 2.4 x 10-2 x 2π x 9 = 0.15 V
But the answer is 0.077 V so my answer is off by factor of two.
Is my mistake related to "emf produced across the side of AC of the coil"?
Thanks
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Summary:: .
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But that made me wonder what would happen if one...
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The question I'm in doubt about is
The motor coil has a resistance of 10 Ω and is powered by a voltage of 120 V. When the motor is operating at rated speed, its emf is 70 V. Thus, it is questioned:
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b) What is the coil current at rated...
Hello, am kind of new to all the physics stuff , and kind a terrible at maths but am trying my best to be good at it one day .So i was told to answer this question
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I've been told that if you drop a magnet through a coil the induced emf and flux graphs would look like this:
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I'm trying to complete this past exam paper Q.
Water volume = 200hl = 20000L
1L=10^-3 m^3
20000L = 200 m^3
Density of water at 15 deg C = 999 kg m^3
Density = Mass/Volume
999 kg m^3 = Mass/(200 m^3)
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Q =m C dT
=...
So my idea was that to reach the equilibrium position, the final moment of force has to be 0 (so in the end the forces will “eliminate” each other). And I found the equation Fm=B*I*l*sinα, which should characterize the force, which affects wire with the current in a magnetic field, and Fleming’s...
The experiment consists of a large field coil (connected to a current source) surrounding a coplanar and coaxial small detector coil in the center of the field coil connected to the oscilloscope.
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Example of one pair of graphs (I'll...
I am doing core loss calculations in Ansys Maxwell for a project, in which I need to draw a helical coil around a rectangular core to get a more realistic model. But I haven't really found any helpful material. I don't know if its possible, but if it is I would really appreciate your help. Thank...
I'll try to explain to you my thinking behind this problem... tell me if it's correct or not.
In short, I have assumed the area enclosed between the wire and the left side of the coil to be ##A## in which is present a ##-\hat{z}## field, and noticed that the flux it generates must be canceled by...
I managed to solve this problem by writing the total E.M.F. as the sum of the one which would have been induced with only the magnetic field varying(and constant ##A##), and that with only the area varying(and constant ##B##).
However, I got to this solution(which doesn't totally convince me)...
It is long known that the toroidal field alone is not sufficient to achieve toroidal force balance within a tokamak due to the field being bent and geometry restricting the field to be of even strength both within the inner and outer circumference of the ring. Induced current is thus used for...
Assume a solenoid coil(made up of ##N## windings) placed in the horizontal(##\hat{y}##) direction and in a constant uniform magnetic field.
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The present setup is a step-down transformer.
Im thinking if n1 is decreased to match or be less than n2, then it will be a step up transformer.
so A.
(but answers say B)?
Attached is a photo the the primary transformer coil of a QI (I believe pronounced CHEE) wireless charger, as used for charging a cell phone. I know the fields of solenoids but what would be the magnetic field structure of this. By-the-way, a similar coil was used on old AM radio sets.
Hi.
At school, I once worked with a Teltron tube that looked very much like this (I don't remember the brand):
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Surely a tough one, I am doing it from the basics. This is the diagram i tried to draw showing the Force and current I
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Faraday's law of induction for the induced EMF ##V_c## in a coil...
It is just for teaching experience sharing. Consider a uniform disk. A stretchless and massless wire has been wound on the disk. The end of the wire is attached to the ceiling. Initially the system is at rest as it is shown at the picture. Then the disk is released. It falls down and rotates and...
I don't really know but if I were to guess it would be based on how many turns are in the coil, the diameter of the coil and the flux of the magnet. Unfortunately I couldn't find a formula anywhere.
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Hi.
I am reading a textbook about simple DC generator. The situation is if we are rotating a single armature coil within a constant field B,
the induced emf will be (if we are to only think about the magnitude), emf= B*l*W*omegaB = magnetic field
l = length of the coil
W = width of the coil...
I require a small conical spring to open from its compressed pancake height of its wire diameter to a free length of 11mm > 0.2 seconds (20 milliseconds)
The large end outer diameter = 7.80mm.
The small end inner diameter must be greater than or equal to 2.75mm.
The conical's spring's will be...
a. No, because only permanent magnets are suitable to be used as a compass.
b. Yes, but only if the coil doesn't have an iron core.
c. Yes, but only if the coil can turn easily.
I choose (c) , Is that correct ?