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.
Q. Why is the EMF zero when the coil is passing through the exact center of the magnet?
The emf is only zero for an instant as the magnet passes through the exact centre of the coil. This is because the effect of the N pole at the one end of the magnet on that end of the coil, is exactly cancelled out by the effect of the S pole of the magnet on the other end of the coil.
Q. What do you observe when the magnet is removed from the coil?
When we pull the magnet out, the left hand end of the coil becomes a south pole (to try and hold the magnet back). Therefore the induced current must be flowing clockwise. Although it is the coil that is moving, this works on the same principle – a magnet magnetic field moving relative to a coil.
Q. What is the average induced emf in the coil?
Average induced emf equals to the change in magnetic flux over time. Thus, the induced emf would be 0.
Q. How do you calculate the emf of a coil?
The induced emf in a coil is equal to the negative of the rate of change of magnetic flux times the number of turns in the coil.
Q. How do you calculate the induced emf of a coil?
Calculating the induced EMF Faraday’s law states: Induced EMF is equal to the rate of change of magnetic flux. Magnetic flux = Magnetic field strength x Area = BA. Therefore…Induced EMF = (change in Magnetic Flux Density x Area)/change in Time. Therefore, Induced EMF = (Bπr2n)/t.
Q. What is the average induced emf?
The magnitude of the average induced emf is: emf = DF/Dt = (Fi – Ff)/Dt = (0.085T – (-0.057T))/1.5s = 0.095V = 95mV.
Q. In which case is there no induced electromagnetic force?
Although the stationary magnet might produce a large magnetic field, no EMF can be induced because the flux through the coil is not changing. When the magnet moves closer to the coil the flux rapidly increases until the magnet is inside the coil.
Q. Why is EMF induced in an AC generator?
An AC (alternating current) generator utilizes Faraday’s law of induction, spinning a coil at a constant rate in a magnetic field to induce an oscillating emf. The coil area and the magnetic field are kept constant, so, by Faraday’s law, the induced emf is given by: If the loop spins at a constant rate, .
Q. What is the EMF equation of generator?
As the armature rotates, a voltage is generated in its coils. In the case of a generator, the emf of rotation is called the Generated emf or Armature emf and is denoted as Er = Eg. In the case of a motor, the emf of rotation is known as Back emf or Counter emf and represented as Er = Eb.
Q. What is back emf equation?
Net voltage = supply voltage + back EMF Back EMF = -45 V. Net voltage across the motor, calculated according to Ohm’s Law (V = I x R = 10 A x 15 Ω), = 150 V.
Q. What is back EMF in DC generator?
When the armature of a DC motor rotates under the influence of the driving torque, the armature conductors move through the magnetic field and hence emf is induced in them as in a generator. The induced emf acts in opposite direction to the applied voltage V (Lenz’s law) and is known as Back EMF or Counter EMF (Eb).
Q. What causes back EMF in a DC motor?
Back EMF in DC Motor. When the current-carrying conductor placed in a magnetic field, the torque induces on the conductor, the torque rotates the conductor which cuts the flux of the magnetic field. Thereby the emf is known as the counter emf or back emf.
