With increase in temperature, the electrical conductivity of semiconductors_____________________?

Related Mcqs:

1. The temperature at which the magnetic property of iron disappears (i.e., it becomes nonmagnetic) and its electrical conductivity & specific heat also changes, is called the ‘Curie point’, which is ________________ °C ?

   A. 768
   B. 908
   C. 1400
   D. 1539

2. Free energy, fugacity and activity co-efficient are all affected by change in the temperature. The fugacity co-efficient of a gas at constant pressure ______________ with the increase of reduced temperature?

   A. Decreases
   B. Increases
   C. Remains constant
   D. Decreases logarithmically

3. The wet bulb temperature is lower in dry air than in wet air at the same temperature. A dry bulb thermometer registers a higher temperature than a wet bulb thermometer except at ______________ percent relative humidity ?

   A. 0
   B. 100
   C. 50
   D. None of these

4. Joule-Thomson co-efficient which is defined as, η = (∂T/∂P)H = 1/Cp (∂H/∂T)P, changes sign at a temperature known as inversion temperature. The value of Joule-Thomson co-efficient at inversion temperature is ___________________?

   A. 0
   B. ∞
   C. +ve
   D. -ve

5. Critical solution temperature (or the con-solute temperature) for partially miscible liquids (e.g., phenol-water) is the minimum temperature at which___________________?

   A. A homogeneous solution (say of phenol water) is formed
   B. Mutual solubility of the two liquids shows a decreasing trend
   C. Two liquids are completely separated into two layers
   D. None of these

6. Major sources of noise in furnace operation arises from air inspirators, combustion, side wall vibrations and fluctuation in the process heat load. A 50% increase in fuel firing rate may increase the furnace noise level by about ____________ decibels?

   A. 3
   B. 30
   C. 7
   D. 70

7. Which of the following liquid metals has the highest thermal conductivity ?

   A. Molten sodium
   B. Molten lead
   C. Mercury
   D. Molten potassium

8. According to the kinetic theory, the thermal conductivity of a monatomic gas is proportional to___________________?

   A. T
   B. T0.5
   C. T1.5
   D. T2

9. With increase in temperature, the atomic heat capacities of all solid elements_________________?

   A. Increases
   B. Decreases
   C. Remains unchanged
   D. Decreases linearly

10. The vapor pressure of liquids of similar chemical nature at any particular temperature _______________ with increase in the molecular weight?

    A. Increases
    B. Decreases
    C. Remains unchanged
    D. Either A. or B.; depends on the liquid