# How is the emf across primary and secondary coils of a transformer?

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## How is the EMF across primary and secondary coils of a transformer related with number of turns of coil in them?

The alternating magnetic flux produced by this current links the secondary coil and induces an emf in it. … The output voltage across the secondary coil depends on the input voltage across the primary coil and the ratio of a number of turns in the secondary coil to that in the primary coil (also known as turns ratio).

## How is EMF induced in secondary coil?

An alternating current passing in one coil (the primary) induces an e.m.f. in an adjacent coil (the secondary). … If there is a complete circuit, there is also an induced current. In a transformer: alternating current in the primary produces an alternating magnetic field.

## How the EMF per turn in the secondary winding of a transformer is related to the EMF per turn of the primary?

In a transformer primary volt-ampere is equal to secondary volt-ampere and primary ampere turns are also equal. So, EMF per turn in both the winding are equal. Total induced emf on both sides depends on the number of turns, flux and frequency.

## Is emf induced in primary coil?

2.5) The change in current Δi1 through the primary coil, by Faraday’s law, induces an EMF in the primary coil. By Lenz’s law, the direction of this EMF is such that it OPPOSES the change in current that produced the changing magnetic field.

## How do you find the emf of a secondary coil?

Vp = N1B/dt. Since ΦB is the same for the secondary coil, the induced emf in the secondary coil is εs = N2B/dt. As long as no load is connected, we measure an output voltage Vs = N2B/dt.

## How is current induced in a secondary coil related to current in a primary coil?

An alternating current passes through a primary coil wrapped around a soft iron core. The changing current produces a changing magnetic field. This induces an alternating voltage in the secondary coil. This induces an alternating current (AC) in the circuit connected to the secondary coil.

## Why an emf is induced in the coil as it rotates?

Hint: Induced emf is generated in a rotating coil when the angle between area vector and magnetic field changes continuously, hence changing the amount of magnetic flux through the coil.

## How do you find secondary emf?

EMF equation of Transformers:

1. N2 = number of turns in secondary windings.
2. E1 = 4.44fN1Φ m
3. E1 = 4.44fN1BA.
4. E2 = 4.44fN2BA.
5. E1/N1 = E2/N2 = 4.44fΦ m
6. E2/E1 = N2/N1 =k.
7. If N2>N1 i.e. K>1, then transformer is called Step up transformer .
8. If N2<N1 i.e. K<1, then transformer is called Step down transformer .

## What happens in the secondary coil of a transformer?

We can make the magnetic field carry on changing by using an alternating current in the primary coil. This produces a magnetic field in the secondary coil. Since the current is alternating, the magnetic field also alternates back and forth. This changing magnetic field induces an alternating EMF in the secondary coil.

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## How does the transformer transfer energy from primary to secondary?

When there is a steady current in the primary there is no effect in the secondary, but there is an effect in the secondary if the current in the primary is changing. A changing current in the primary induces an e.m.f. in the secondary. If the secondary is connected to a circuit then there is a current flow.