Motional emf i thinkchange in area and magnetic field

In summary, the area of the coil increases at a rate of 5.2 10-3 m2/s, and the magnitude of the emf induced in the coil is -0.12 V.
  • #1
goWlfpack
51
0
motional emf i think... change in area and magnetic field

Homework Statement



A rectangular loop is located in a uniform magnetic field of magnitude 0.29 T directed perpendicular to the plane of the coil. If the area of the coil increases at the rate of 5.2 10-3 m2/s, what is the magnitude of the emf induced in the coil?

Homework Equations



ummmm maybe emf=blv
emf=-L (I/t)


The Attempt at a Solution



honestly i don't even understand conceptually what is going on in this problem so it is hard for me to find any equation(s) to help me solve it. The area of the coil decreases? that doesn't make sense to me and i have no idea what correlation that has to magnetic field other then flux=BA... so help?
 
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  • #2


Faraday's law relates EMF to the rate of change of the flux. (See: Faraday's Law.) What's the rate of change of the flux?
 
  • #3


Doc Al said:
Faraday's law relates EMF to the rate of change of the flux. (See: Faraday's Law.) What's the rate of change of the flux?

Well the change in magnetic flux would be flux=B(deltaA)

so the change in flux should equal .001508

then faraday's law is emf=-N (change in flux)/change in time

but there arent any turns in this wire and also there is no time given. but if you put in 1 for each you get the change in flux which got a red x...ugh
 
  • #4


Try this:

Flux = BA, but B is fixed so only A changes.

Δ(Flux)/Δt = Δ(BA)/Δt = B ΔA/Δt
 
  • #5


Doc Al said:
Try this:

Flux = BA, but B is fixed so only A changes.

Δ(Flux)/Δt = Δ(BA)/Δt = B ΔA/Δt


ok so that gives me the change in flux. But how do i go about getting the emf without having a value for "N" or the number of turns?
 
  • #6


It's a single loop--so what do you think N is? :wink:
 

1. What is motional emf?

Motional emf, also known as induced emf, is the voltage generated in a conductor when it moves through a magnetic field. This phenomenon is governed by Faraday's law of induction, which states that a changing magnetic field induces an electric field in a conductor.

2. How does a change in area affect motional emf?

A change in the area of a conductor moving through a magnetic field will result in a change in the magnetic flux, which in turn will induce a motional emf. The greater the change in area, the greater the induced emf.

3. How does a change in magnetic field affect motional emf?

A change in the strength of the magnetic field will also result in a change in the magnetic flux, and therefore a change in the induced emf. The greater the change in magnetic field, the greater the induced emf.

4. What is the relationship between velocity and motional emf?

The velocity of the conductor moving through the magnetic field will affect the magnitude of the induced emf. The faster the velocity, the greater the induced emf. This is because a faster-moving conductor will experience a greater change in magnetic flux over time.

5. What are some real-world applications of motional emf?

Motional emf has many practical applications, such as in generators and electric motors. It is also used in devices like magnetic levitation trains and particle accelerators. Additionally, it is the principle behind the operation of magnetic flowmeters, which are used to measure the flow rate of conductive liquids.

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