Ques_Ans 10-30 words

[35]      What is dissipation factor?

It is the ratio between the power wasted per cycle and the power stored per cycle.

[36]      What is reluctance?

It is the property of a magnetic material by which it opposes the establishment of magnetic flux.

[37]      What is retentivity?

The retaining capacity of magnetism of a magnetic material after the removal of inducing agency is called retentivity.

[38]      What is self inductance?

The property of coil by which it opposes the change in the value of current or flux through it due to the production of self induced emf is called self inductance.

[39]      What is mutual inductance?

The ability of one coil to produce an emf in the nearby coil due to the change of current or flux in the first coil is called mutual inductance.

[40]      How the dynamically induced emf is produced?

The dynamically induced emf is produced by moving the coil and keeping the magnet stationary or vice versa.

  30-60 words

[1]        What is leakage flux and useful flux?

The flux that follows an undesired path is called leakage flux. To utilize the magnetic flux established by the magnetic material, an air gap is provided. The flux in the air gap is called useful flux, the flux which does not pass through air gap cannot be utilized hence it is considered as leakage flux.

  60-100 words

[1]        What is Fleming’s right hand rule?

This is used to determine the direction of emf induced. According to this, the thumb, fore finger

And middle finger of the right hand are kept at right angles to one another and if the fore finger

Represents the direction of magnetic lines of flux, the thumb indicates the direction of motion of the conductor, and then the middle finger will indicate the direction of induced emf.

[2]        What is Fleming’s left hand rule?

This is used to determine the direction of the force acting on a current carrying conductor placed

in the magnetic field. According to this rule, the thumb, fore finger and middle finger of the left

Hand at right angles to one another and if the first finger represents the direction of magnetic field, the middle finger indicates the direction of current then the thumb will indicate the direction of force acting on the conductor.

[3]        Compare magnetic and electric circuits.

In the electric circuit, electric current flows whereas in a magnetic circuit the magnetic flux does

Not flow. The reluctance of the magnetic circuit varies with flux density, whereas the resistance remains practically constant with current strength. Reluctance of the magnetic circuit is similar to that of resistance in electric circuit. The magneto-motive force in a circuit is similar to Electromotive force in electric circuit.