Question

What is motional emf? State any two factors on which it depends.

Answer 1

Hint: In this, there will be a change in the field due to some kind of motion and also if the loop moves into or out of a specified region of the field then the emf will get induced. By using these statements we can understand the motional emf and can answer this.

Complete Step by Step Solution: An emf induced by motion relative to a magnetic field $B$ is called as Motional emf
\[ \Rightarrow emf = Blv\]
Where,
$B$ , is the uniform magnetic field, $v$ is the velocity and, $l$ is the length.
All three are perpendicular to each other.
The factors on which Motional emf depends are nothing but, the magnetic field and velocity and length of the rod.

Additional information: Electromotive force is the energy per unit electric charge that is imparted by the energy source, such as an electric generator. Energy is converted from one form to another in the generator as the device does work on the electric charge being transferred within itself. One terminal of the device becomes positively charged, another becomes negatively charged. The work is done or the energy gained per unit electric charge is the electromotive force.
It is commonly measured in units of volts or one erg per electrostatic unit of charge
Induced emf can be defined as the generation of a potential difference in a coil due to the changes in the magnetic flux through it.
Electromotive forces can be induced in two different ways,
This way involves the placement of an electric conductor in a magnetic field that is moving.
This way involves the placement of a constantly moving conductor of electricity into a magnetic field that is static in nature.
Induced emf can be used in generators, transformers, and in a galvanometer.

Note: Motional and induced emf both are induced the only difference being that the previous is through the rate of change of current and the latter will be for the rotation or motion. In transformers, only the former is present whereas in the rotating electrical machine both are present.