Home
Class 12
PHYSICS
A piece of copper and another of germani...

A piece of copper and another of germanium are cooled from room temperature to 100 K. What will happen to their conductivities? Explain.

Text Solution

Verified by Experts

Conductivity of a metal increases when it is cooled due to decrease in its resistance. Conductivity of semi conductors decreases on its cooling because energy gap between conduction band and valence band increases on cooling (with decrease in temperature).
Promotional Banner

Topper's Solved these Questions

  • ELECTRIC CURRENT, RESISTANCE AND E.M.F.

    BETTER CHOICE PUBLICATION|Exercise LONG ANSWERTYPE QUESTIONS |8 Videos

  • ELECTRIC CURRENT, RESISTANCE AND E.M.F.

    BETTER CHOICE PUBLICATION|Exercise NUMERICAL PROBLEMS|54 Videos

  • ELECTRIC CURRENT, RESISTANCE AND E.M.F.

    BETTER CHOICE PUBLICATION|Exercise MOST EXPECTED QUESTIONS |14 Videos

  • ELECTRIC CHARGES AND ELECTROSTATIC FORCE

    BETTER CHOICE PUBLICATION|Exercise NUMERICAL PROBLEMS (MOST EXPECTED NUMERICALS )|6 Videos

  • ELECTRIC FIELD

    BETTER CHOICE PUBLICATION|Exercise NUMERICAL PROBLEMS (MOST EXPECTED QUESTIONS)|4 Videos

Similar Questions

Explore conceptually related problems

A strip of copper another of germanium are cooled from room temperature to 80 K. The resistance of

A piece of germanium and another of copper are stated to experience a rise in temperature. The resistance of

Pragya tested the solubility of three different substances at different tem¬ peratures and collected the data as given below (results are given in the following table, as grams of substance dissolved in 100 grams of water to form a saturated solution).Pragya makes a saturated solution of potassium chloride in water at 353 K and leaves the solution tocool atroom temperature. What would she observe asthesolution cools ? Explain

In an intrinsic semiconductor the energy gap E_g is 1.2eV . Its hole mobility is much smaller than electron mobility and independent of temperature. What is the ratio between conductivity at 600K and that at 300K? Assume that the temperature dependence of intrinsic carrier concentration ni is given by n_i= n_0 exp((E_g)/(2k_BT)) where n_0 is constant.

What is the effect of rise in temperature on the conductivity of copper and silicon ?

BETTER CHOICE PUBLICATION-ELECTRIC CURRENT, RESISTANCE AND E.M.F.-SHORT ANSWER TYPE QUESTIONS
  1. Explain the effect of temperature on the resistivity of pure semicondu...

    Text Solution

    |

  2. Difference between ohmic and non ohmic devices.

    Text Solution

    |

  3. A piece of copper and another of germanium are cooled from room temper...

    Text Solution

    |

  4. V-I graph for a mettalic wire at two different temperatures T1 and T2 ...

    Text Solution

    |

  5. On what factors does the internal resitance of the cell depend?

    Text Solution

    |

  6. Is a wire carrying current charged?

    Text Solution

    |

  7. What is non-ohmic device? Give one example.

    Text Solution

    |

  8. If the electron drift speed is so small and the electron's charge is s...

    Text Solution

    |

  9. A large number of free electrons are present in metals. Why is there n...

    Text Solution

    |

  10. Standard resistance coils are made of which materials and why ?

    Text Solution

    |

  11. Discuss the effect of temperature on resistivity of metals.

    Text Solution

    |

  12. Why conducting wires are made of copper?

    Text Solution

    |

  13. What is the resistance of a conductor? State the factors on which resi...

    Text Solution

    |

  14. What is the difference between e.m.f. and potential diffrence?

    Text Solution

    |

  15. What are ohmic and non-ohmic resistors? Give one example of each.

    Text Solution

    |

  16. What is e.m.f. of a cell ? On what factors does its value depend ?

    Text Solution

    |

  17. Establish the relation between current and drift velocity?

    Text Solution

    |

  18. Define drift velocity of electricity and establish its relation with v...

    Text Solution

    |

  19. Obtain the condition fo rmaximum current through a resisitor, when a n...

    Text Solution

    |

  20. Define internal resistance of cell and find an expression for it.

    Text Solution

    |