Why induced EMF is called back EMF?

Content Curator

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

Also check:

Important Topics from EMF
EMF MCQs	Electrical Current	Types of Current
EMF Important Questions	Electrical Resistance	Cells In Series and Parallel
Relation between Resistance and Length	Potentiometer	Meter Bridge
Wheatstone Bridge	Kirchhoff’s Rules	Potentiometer

CBSE CLASS XII Related Questions

1.
In a telescope the objective has much larger aperture than the eye piece. Why ?

View Solution

2.
Two air-filled capacitors of capacitances $C_1$ and $C_2$ are connected in parallel with a dc battery. After the capacitors are fully charged, a slab of dielectric constant K is inserted between the plates of each capacitor. How will the (i) charge on each capacitor and (ii) energy stored in the capacitor affected after the slab is introduced.

View Solution

3.
An astronomical telescope consists of two converging lenses. One of them of large aperture and large focal length is called objective lens and the other one, of smaller focal length and smaller aperture is called the eyepiece. It is used to see distant objects which are not seen clearly with naked eyes. The image formed by the objective lens acts as an object for the eyepiece and the final image produced by the eyepiece is magnified.

4.
Two copper wires having their radii in the ratio of 3 : 2 are connected in series across a battery. Find the ratio of the drift velocities of the electrons in the wires.

View Solution

5.
An electric field $\vec{E}$ is established across the ends of a cylindrical conductor of length L and area of cross-section A. Discuss how electrons attain an average velocity, independent of time. Hence, obtain a relation between current in the conductor and this ‘average velocity’ of electrons.

View Solution

6.
This ‘average velocity’ is found be few mm/s for currents in range of a few amperes. How then is current established almost the instant a circuit is closed ?

View Solution

Why induced EMF is called back EMF?

CBSE CLASS XII Related Questions

1.
In a telescope the objective has much larger aperture than the eye piece. Why ?

4.
Two copper wires having their radii in the ratio of 3 : 2 are connected in series across a battery. Find the ratio of the drift velocities of the electrons in the wires.

6.
This ‘average velocity’ is found be few mm/s for currents in range of a few amperes. How then is current established almost the instant a circuit is closed ?

Similar Physics Concepts

Comments

SUBSCRIBE TO OUR NEWS LETTER

Why induced EMF is called back EMF?

CBSE CLASS XII Related Questions

1.In a telescope the objective has much larger aperture than the eye piece. Why ?

4.Two copper wires having their radii in the ratio of 3 : 2 are connected in series across a battery. Find the ratio of the drift velocities of the electrons in the wires.

6.This ‘average velocity’ is found be few mm/s for currents in range of a few amperes. How then is current established almost the instant a circuit is closed ?

Similar Physics Concepts

Comments

SUBSCRIBE TO OUR NEWS LETTER

1.
In a telescope the objective has much larger aperture than the eye piece. Why ?

4.
Two copper wires having their radii in the ratio of 3 : 2 are connected in series across a battery. Find the ratio of the drift velocities of the electrons in the wires.

6.
This ‘average velocity’ is found be few mm/s for currents in range of a few amperes. How then is current established almost the instant a circuit is closed ?