26. Piezoelectricity has been observed in:

1. 1. nickel

   
   
   

   2. glass

   
   
   

   3. quartz

   
   
   

   4. mica

   
   
   

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   NA

   Correct Option: C

   NA

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27. A ferroelectric material exhibits:

1. 1. spontaneous magnetisation

   
   
   

   2. hysteresis effect with polarization

   
   
   

   3. no spontaneous magnetisation

   
   
   

   4. superconducting states

   
   
   

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   A ferroelectric material exhibits hysteresis effect with polarization.

   Correct Option: B

   A ferroelectric material exhibits hysteresis effect with polarization.

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28. Insulating materials that can withstand a temperature above 180°C is of:

1. 1. class A type

   
   
   

   2. class B type

   
   
   

   3. class C type

   
   
   

   4. class H type

   
   
   

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   NA

   Correct Option: C

   NA

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29. Polarization in polyatomic gases is the sum of (notations carry their usual meaning):

1. 1. P_e + P_o + P_i + P_s

   
   
   

   2. P_e only

   
   
   

   3. P_e + P_i

   
   
   

   4. P_e + P_o + P_i

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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30. Volume imperfections can be of the type of:

1. 1. Schottky’s defect

   
   
   

   2. twin

   
   
   

   3. stacking fault

   
   
   

   4. noncrystalline regions

   
   
   

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1. View Hint View Answer Discuss in Forum

   Volume imperfections can be of the type of noncrystalline regions

   Correct Option: D

   Volume imperfections can be of the type of noncrystalline regions

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