Question: Why Is EMF Max When Flux Is Zero?

Is Flux a vector?

For transport phenomena, flux is a vector quantity, describing the magnitude and direction of the flow of a substance or property.

In vector calculus flux is a scalar quantity, defined as the surface integral of the perpendicular component of a vector field over a surface..

What is the difference between flux and flux density?

The amount of magnetic flux a magnet displays is a direct result of the material that makes up the magnet. The magnetic flux density is a product of the magnetic flux and the area that this flux is present within.

What is the definition of magnetic field?

Magnetic field, a vector field in the neighbourhood of a magnet, electric current, or changing electric field, in which magnetic forces are observable. …

What is the formula for EMF?

The emf is equal to the work done on the charge per unit charge (ϵ=dWdq) when there is no current flowing. Since the unit for work is the joule and the unit for charge is the coulomb, the unit for emf is the volt (1V=1J/C).

How do you calculate Max EMF?

emf=2Bℓw2ωsinωt=(ℓw)Bωsinωt emf = 2 B ℓ w 2 ω sin ⁡ ω t = ( ℓ w ) B ω sin ⁡ . is the maximum (peak) emf. Note that the frequency of the oscillation is f = ω/2π, and the period is T = 1/f = 2π/ω.

How magnetic flux can be zero when the magnetic field is not zero?

The magnetic flux is generated when a change in the magnitude and direction of the magnetic field occurs. If the magnetic field is parallel to the place of the area that is exposed, then the magnetic flux generated is zero when the magnetic field is not zero.

What is N in Faraday’s Law?

For a tightly wound coil of wire, composed of N identical turns, each with the same ΦB, Faraday’s law of induction states that. where N is the number of turns of wire and ΦB is the magnetic flux through a single loop.

What does eddy current mean?

Eddy currents (also called Foucault’s currents) are loops of electrical current induced within conductors by a changing magnetic field in the conductor according to Faraday’s law of induction. … This effect is employed in eddy current brakes which are used to stop rotating power tools quickly when they are turned off.

What is the basic cause of induced emf?

The basic cause of induced emf is the change of magnetic flux linked with a closed circuit.

What is motional EMF?

An emf induced by motion relative to a magnetic field B is called a motional emf and is given by. emf = Bℓv (B,ℓ, and v perpendicular) where ℓ is the length of the object moving at speed v relative to the field.

What is unit of flux density?

Magnetic flux density has the dimension mass per time squared electric current. The SI derived unit of magnetic flux density is the tesla, which is defined as a volt second per square meter.

Why is the EMF maximum when the plane of the armature is parallel to the magnetic field?

When the plane of the armature is parallel to the lines of force of magnetic field, the rate of change of magnetic flux linked with it is maximum. Therefore, the e.m.f. induced in the armature in this orientation is maximum.

Why the magnetic flux on a closed surface is zero?

Because magnetic field lines are continuous loops, all closed surfaces have as many magnetic field lines going in as coming out. Hence, the net magnetic flux through a closed surface is zero.

How do you find maximum EMF?

E.m.f. generated in a rotating coilE = BANωsinθ = BANωsin(ωt) The maximum value of the e.m.f (Eo) is when θ (= ωt) = 90o (that is, the coil is in the plane of the field, Figure 2) and is given by.Maximum e.m.f (Eo) = BANω … The r.m.s value of the e.m.f is (Er.m.s) = BANω/21/2 … A VERSION IN WORD IS AVAILABLE ON THE SCHOOLPHYSICS USB.

Can you have negative EMF?

Faraday’s law can be written: The negative sign in Faraday’s law comes from the fact that the emf induced in the coil acts to oppose any change in the magnetic flux.

Why is EMF zero when magnetic flux is maximum?

An emf is induced in the coil because of this changing magnetic flux. … By Faraday’s law, the magnitude of the induced emf is equal to the rate of change of magnetic flux, so its maximum values occurs when the flux curve has its greatest slope. The induced emf goes through zero when the flux curve has zero slope.