EMF induced via change in magnetic flux vs. velocity in magnetic field

In summary, the induced voltage in a rotating loop will be maximum at 90 and 270 degrees due to the perpendicular direction of the loop's velocity and the magnetic field. This can be calculated using the equation emf = L (v * B). Lenz's law may come into play, but it is not mentioned in the answer. The resistance of the loop may affect the induced voltage through the voltage drop across the loop.
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Homework Statement


(See attached diagram)--Note this problem was taken from Barron's SAT Physics Practice Test 1 #58
As the loop rotates, the induced voltage will be maximum at...
a) 0 degrees and 90 degrees
b) 0 degrees and 180 degrees
c) 90 degrees and 270 degrees
d) 180 degrees and 270 degrees
e) it will be constant throughout rotation

Homework Equations


emf = -Δ∅/Δt
emf = L (v * B)

The Attempt at a Solution


The answer simply states that since the line of wire's direction of velocity is most perpendicular to B (the magnetic field) at 90 and 270 degrees, using emf = L (v * B) (where "*" denotes cross-product), then the emf will be maximized at 90 and 270.

However the answer never says anything about Lenz's law, so how would that play into everything? Wouldn't the change in flux through the loop cause a reverse current (with respect to the current caused by emf = LvB) at some degrees? Or is there a reason why we don't consider Lenz's law here?
 

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Also, what role does the resistance of the loop have in all this? I see that the resistance is connected to the voltage drop across the loop, meaning that the greater the resistance, the greater the voltage drop. But how does this affect the induced voltage?
 

What is EMF?

EMF stands for electromagnetic force, which is a force that is created when a magnetic field interacts with an electrically charged object. It is a fundamental concept in electromagnetism and plays a crucial role in various fields such as physics, engineering, and medicine.

How is EMF induced through a change in magnetic flux?

EMF can be induced in a conductor when there is a change in the magnetic flux passing through it. This change in magnetic flux can be caused by either moving the conductor across a stationary magnetic field or by changing the strength of the magnetic field itself. This phenomenon is known as electromagnetic induction, and it is the basis for many technologies such as generators and transformers.

What is the relation between EMF and velocity in a magnetic field?

The relation between EMF and velocity in a magnetic field is described by Faraday's law of electromagnetic induction. It states that the magnitude of the induced EMF is directly proportional to the rate of change of magnetic flux through a conductor. This means that as the velocity of the conductor increases, the induced EMF also increases.

What factors affect the magnitude of EMF induced?

The magnitude of EMF induced through a change in magnetic flux can be affected by several factors such as the strength of the magnetic field, the velocity of the conductor, and the angle between the magnetic field and the conductor. Additionally, the length and shape of the conductor and the material it is made of can also impact the induced EMF.

How is EMF induced via change in magnetic flux used in everyday life?

There are numerous applications of EMF induced via change in magnetic flux in our daily lives. Some examples include electric generators that convert mechanical energy into electrical energy, transformers that step up or step down voltage levels, and induction cooktops that use electromagnetic induction to heat up pots and pans. It is also used in various medical devices, such as MRI machines, to produce images of the human body.

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