Why induced EMF is called back EMF?

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The term "back EMF" is used in relation to the phenomenon of electromagnetic induction. When a magnetic field is changed, it produces an electromotive force (EMF) across a conductor placed within the field. This induced EMF is in opposition to the change in the magnetic field that is producing it, and therefore it is called "back EMF."

For example, when a coil of wire is placed within a magnetic field and the magnetic field is varied, it induces an EMF in the coil. If the magnetic field is increasing, the induced EMF will be in the opposite direction of the magnetic field, acting as a brake. This is because the induced current produced by the EMF produces its own magnetic field, which opposes the original field.

In other words, the induced EMF acts as a "backwards" force, resisting the change in magnetic field that is producing it. This is why it is called "back EMF." It is important to note that the direction of the induced EMF is always such that it opposes the change that is causing it, following Lenz's Law.

Back EMF

Back EMF

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CBSE CLASS XII Related Questions

1.
Two heaters rated as \((P_1,V)\) and \((P_2,V)\) are connected in series across a dc source of \(V/2\) volt. The power consumed by the combination will be –

\((P_1+P_2)\)
\(\dfrac{P_1+P_2}{2}\)
\(\dfrac{P_1P_2}{2(P_1+P_2)}\)
\(\dfrac{P_1P_2}{4(P_1+P_2)}\)

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2.
The figure shows three point charges kept at the vertices of triangle ABC. The net electric field, due to this system of charges, at the midpoint M of base BC will be:

\( \frac{q}{4 \pi \epsilon_0 l^2} \) pointing along MA
\( \frac{q}{\pi \epsilon_0 l^2} \) pointing along AM
\( \frac{q}{2 \pi \epsilon_0 l^2} \) pointing along AM
Zero

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3.
Two parallel plate capacitors X and Y are connected in series to a 6 V battery. They have the same plate area and same plate separation but capacitor X has air between its plates, whereas capacitor Y contains a material of dielectric constant 4. Calculate the capacitances of X and Y, if the equivalent capacitance of the combination of X and Y is \( 4 \, \mu\text{F} \). Calculate the potential difference across the plates of X and Y.

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4.
Draw the number of scattered particles versus the scattering angle graph for scattering of alpha particles by a thin foil. Write two important conclusions that can be drawn from this plot.

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5.
Two small identical metallic balls having charges \( q \) and \( -2q \) are kept far at a separation \( r \). They are brought in contact and then separated at distance \( \frac{r}{2} \). Compared to the initial force \( F \), they will now:

attract with a force \( \frac{F}{2} \)
repel with a force \( \frac{F}{2} \)
repel with a force \( F \)
attract with a force \( F \)

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6.
Assertion (A) : All atoms have a net magnetic moment. Reason (R) : A current loop does not always behave as a magnetic dipole.

Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
Assertion (A) is true, but Reason (R) is false.
Both Assertion (A) and Reason (R) are false.

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Why induced EMF is called back EMF?

CBSE CLASS XII Related Questions

1.
Two heaters rated as \((P_1,V)\) and \((P_2,V)\) are connected in series across a dc source of \(V/2\) volt. The power consumed by the combination will be –

2.
The figure shows three point charges kept at the vertices of triangle ABC. The net electric field, due to this system of charges, at the midpoint M of base BC will be:

4.
Draw the number of scattered particles versus the scattering angle graph for scattering of alpha particles by a thin foil. Write two important conclusions that can be drawn from this plot.

5.
Two small identical metallic balls having charges \( q \) and \( -2q \) are kept far at a separation \( r \). They are brought in contact and then separated at distance \( \frac{r}{2} \). Compared to the initial force \( F \), they will now:

6.
Assertion (A) : All atoms have a net magnetic moment. Reason (R) : A current loop does not always behave as a magnetic dipole.

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Why induced EMF is called back EMF?

CBSE CLASS XII Related Questions

1.Two heaters rated as \((P_1,V)\) and \((P_2,V)\) are connected in series across a dc source of \(V/2\) volt. The power consumed by the combination will be –

2.The figure shows three point charges kept at the vertices of triangle ABC. The net electric field, due to this system of charges, at the midpoint M of base BC will be:

4. Draw the number of scattered particles versus the scattering angle graph for scattering of alpha particles by a thin foil. Write two important conclusions that can be drawn from this plot.

5.Two small identical metallic balls having charges \( q \) and \( -2q \) are kept far at a separation \( r \). They are brought in contact and then separated at distance \( \frac{r}{2} \). Compared to the initial force \( F \), they will now:

6.Assertion (A) : All atoms have a net magnetic moment. Reason (R) : A current loop does not always behave as a magnetic dipole.

Similar Physics Concepts

Comments

SUBSCRIBE TO OUR NEWS LETTER

1.
Two heaters rated as \((P_1,V)\) and \((P_2,V)\) are connected in series across a dc source of \(V/2\) volt. The power consumed by the combination will be –

2.
The figure shows three point charges kept at the vertices of triangle ABC. The net electric field, due to this system of charges, at the midpoint M of base BC will be:

4.
Draw the number of scattered particles versus the scattering angle graph for scattering of alpha particles by a thin foil. Write two important conclusions that can be drawn from this plot.

5.
Two small identical metallic balls having charges \( q \) and \( -2q \) are kept far at a separation \( r \). They are brought in contact and then separated at distance \( \frac{r}{2} \). Compared to the initial force \( F \), they will now:

6.
Assertion (A) : All atoms have a net magnetic moment. Reason (R) : A current loop does not always behave as a magnetic dipole.