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Write the mathematical relation for the ...

Write the mathematical relation for the resistivity of a material in terms of relaxation time, number density and mass and charge of charge carriers in it.
Explain, using this relation, why the resistivity of the metal increases and that of a semiconductors decreases with rise in temperature.

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Write a relation between current and drift velocity of electrons in a conductor. Use this relaxation to explain how the resistance of a conductor change with the rise in temperature.

If p is the resistivity of a material, and n is the number density of free electrons in it, the mean time between collisions between electrons in the material is given by: (m denotes the mass of an electron, and e denotes the charge on an electron)

Define relaxation time of the free electrons drifiting in a conductor. Establish a relation between drift. Velocity and time of relaxation. Use this relation to deduce the expression for the electrical resistivity of the material.

MODERN PUBLICATION-CURRENT ELECTRICITY-REVISION EXERCISES (SHORT ANSWER QUESTIONS)
  1. A wire of resistance R, length l and uniform area of cross-section A i...

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  2. A given wire having resistance R is stretched so as to reduce its diam...

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  3. Write the mathematical relation for the resistivity of a material in t...

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  4. Explain with the help of a graph the variation of conductivity with te...

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  5. Write two differences between ohmic circuit and non-ohmic circuit.

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  6. Draw a graph showing the variation of resistivity with temperature for...

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  7. Define the term resistivity of conductor. Give its SI units. Show that...

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  8. If n resistors each of resistance r are connected to get (i) maximum p...

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  9. (a) How will you represent a resistance of 3,700 + 10% ohm by a colour...

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  10. (a) A wire of resistance R, length l and area of cross-section A is cu...

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  11. State Joule's law of heating by electric current. Name the materials u...

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  12. The circuit shown in the diagram contains a battery "B" a rheostat "Rh...

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  13. Define internal resistance of a cell. Prove that r ~= ((E)/(V) - 1)R, ...

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  14. What is emf of a cell? On what factors does its value depend?

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  15. (a) Derive a relation between the internal resistance, emf and termina...

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  16. State the two Kirchhoff's laws.

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  17. A number of indentical cells, n, each of emf epsilon, internal resist...

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  18. State Wheatstone bridge principle and deduce it using Kirchhoff's rule...

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  19. How will you infer with the help of an experiment that the same curren...

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  20. With the help of circuit diagram, explain how a meter bridge can be us...

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