Which energy source is formed when organic matter is trapped underground without exposure to air or moisture?. . A. natural gas.
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Answer:
The Resultant Induced Emf in coil is 4∈.
Explanation:
Given that,
A coil of wire containing having N turns in an External magnetic Field that is perpendicular to the plane of the coil which is steadily changing. An Emf (∈) is induced in the coil.
To find :-
find the induced Emf if rate of change of the magnetic field and the number of turns in the coil are Doubled (but nothing else changes).
So,
Emf induced in the coil represented by formula
∈ = ...................(1)
Where:
. { B is magnetic field }
{A is cross-sectional area}
. No. of turns in coil.
. Rate change of induced Emf.
Here,
Considering the case :-
&
Putting these value in the equation (1) and finding the new emf induced (∈1)
∈1 =
∈1 =
∈1 =
∈1 = 4∈ ...............{from Equation (1)}
Hence,
The Resultant Induced Emf in coil is 4∈.
Explanation:
A transformer consists of core of soft iron (a material that can be easily magnetized/demagnetized), to which two coils are attached at both ends.
An alternating current in the primary coil produces a magnetic field around the coil, magnetizing the iron core; therefore, the same magnetic field produces a magnetic flux in the secondary coil.
Since the AC current in the primary coil is variable, then the magnetic field also changes, so the magnetic flux through the secondary coil changes over time; therefore, an electromotive force (and so, a current) is induced in the secondary coil, according to Faraday-Newmann-Lenz:
where
is the induced emf
is the rate of change of magnetic flux through the secondary coil
We notice that this mechanism would not work if the current in the primary coil is a DC current: in fact, a DC current has always a constant value, so there is no change in the magnetic field, therefore no change in the magnetic flux through the secondary coil and no emf induced.