Homework Statement
A 2200 µF capacitor is charged to a potential difference of 12 V and then discharged through an electric motor. The motor lifts a 50 g mass through a height of 24 cm.
The capacitor is charged to 12 V again and then discharged through a 16 Ω resistor
Determine the time...
I guess the magnetic flux isn't changing, because it's moving at a constant velocity. So that would mean no increase/decrease in the rate of change of magnetic flux, so no induced emf?
Homework Statement
Homework Equations
induced emf = - d(magnetic flux)/dt
The Attempt at a Solution
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I believe the graph will start initially curving upwards, because it begins to cut more and more flux lines which lead to an increased induced emf. Once it is "fully" within the...
Homework Statement
In plane polarised light, the oscillations of the electric field are:
A. in a single plane, which includes the direction of energy transfer.
B. in a single plane, which is perpendicular to the direction of energy transfer
C. in perpendicular planes, which are perpendicular...
Homework Statement
Homework Equations
I'm not sure any, perhaps 1/v + 1/u = 1/f
The Attempt at a Solution
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I knowp enlargened real images will only be produced if the object distance is lower than the image distance, so that rules out B. Similarly I know that enlargened virtual images...
Homework Statement
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A particle detector shows tracks produced by two particles X and Y that were created by the decay of a lambda particle at O.
Which of the following is a correct statement about energy at the decay?
The energy of X must be greater than that of Y.
The combined energy...
now I've got V = B 2 pi r v dt / dt (change in flux over change in time, I guess I can cancel out the dts?)
I = 2 pi r v / R
using F = BIL with L = 2 pi r I get:
mg = B2 4 pi r2 v / R
still I've gone wrong somewhere
The cross-sectional areas I guess don't have flux running through them. So my area would just be 2 pi r * v * dt
Would the length of the current-carrying wire be the circumference of the ring?
The area would be the surface of the cylinder, so perhaps 2pi r2 + 2pi r v dt ?
Would the length then be v * dt perhaps?
For direction of the current, I have using the fleming's right hand rule the motion going downwards, the field going rightwards and thus the current would be coming out of...
So it should be magnetic flux = B * pi r2 for the right dimensions.
L is the length of a current-carrying wire, I thought it would apply to the problem because an emf is being induced in the ring that opposes the flux, and since it's a closed loop there must be current..
I think the magnetic...
Homework Statement
A cylindrical magnet with its axis vertical provides a radial magnetic field. A thin, circular aluminium ring that is co-axial with the magnet falls through the magnetic field.
By finding an expression for the current in the ring when it is falling at the speed v, or...
Homework Statement
Two parallel wires connected to equal sinusoidal alternating currents with a phase difference of pi rad. How does the force of attraction vary with time (draw a graph)?
Q from here...
For centripetal force it's the distance between the mass and the centre.
For Newton's law of gravitation it's the distance between the two objects.
so it should be this?
So F = Mw2R = GMm / r2
So towards the centre point, but I'm guessing I should add the radiuses together perhaps? I'm also confused about the masses here, should I add them together too?