THERMOELECTRIC GENERATOR

Introduction: 

A working of Thermoelectric Generator - (TEG) is based on the direct interconversion of heat and electricity, The Seebeck Effect produces an electric current when dissimilar metals are exposed to a variance in temperature. 

Principle:

when two materials are exposed to different temperatures there is a resultant voltage between the two. Thermoelectric generators take heat input at one end of the material and then induce a voltage due to the difference in temperatures between them. 

There have been different materials that are being used in the thermoelectric generators and a majority of them are now using semiconductors. Thermoelectric power generators have the same basic configuration, as shown in the figure.

WORKING MODULE:

 A circuit containing thermoelectric materials which generate electricity from heat directly. A thermoelectric module consists of two dissimilar thermoelectric materials joined at their ends: an n-type (with negative charge carriers), and a p-type (with positive charge carriers) semiconductor. Direct electric current will flow in the circuit when there is a temperature difference between the ends of the materials.

Important Questions for Class 12 Physics

1. Why do the electrostatic field lines not form closed loops?

Answer:

Electric field lines do not form closed loops because the direction of an electric field is from positive to negative charge. So one can regard a line of force starting from a positive charge and ending on a negative charge. This indicates that electric field . lines do not form closed loops.

2. Why do the electric field lines never cross each other?

Answer:

The electric lines of force give the direction of the electric field. In case, two lines of force intersect, there will be two directions of the electric field at the point of intersection, which is not possible.

3. What is the electric flux through a cube of side 1 cm which encloses an electric dipole? 

Answer:

Zero because the net charge of an electric dipole (+ q and – q) is zero.

4. Why are electric field lines perpendicular at a point on an equipotential surface of a conductor?

Answer:

If the electric field lines were not normal to the equipotential surface, it would have a non-zero component along the surface. To move a unit test charge against the direction of the component of the field, work would have to be done which means this surface cannot be equipotential surface.
Hence, electric field lines are perpendicular at a point on an equipotential surface of a conductor.

5. How does the electric flux due to a point charge enclosed by a spherical Gaussian surface get affected when its radius is increased? 

Answer:

The electric flux due to a point charge enclosed by a spherical gaussian surface remains ‘unaffected’ when its radius is increased.

6 .Does the charge given to a metallic sphere depend on whether it is hollow or solid? Give reason for your answer. 

Answer:

No, it does not, because the charge resides only on the surface of the conductor.