176. Relative permeability of a paramagnetic material is:

1. 1. one

   
   
   

   2. less than one

   
   
   

   3. more than one

   
   
   

   4. several hundreds

   
   
   

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1. View Hint View Answer Discuss in Forum

   Relative permeability of a paramagnetic material is more than one.

   Correct Option: C

   Relative permeability of a paramagnetic material is more than one.

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177. The approximate distance between two atoms in crystal unit cell is:

1. 1. 10 × 10^{– 10} m

   
   
   

   2. 1 × 10^{– 5} m

   
   
   

   3. 2 × 10^{– 10} m

   
   
   

   4. 2 × 10^{– 12} m

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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178. In photoelectron emission, the threshold frequency is defined as the:

1. 1. minimum frequency at which field emission begins

   
   
   

   2. lowest frequency at which photoemission of electron starts

   
   
   

   3. maximum frequency at which photoemission of electron stops

   
   
   

   4. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   In photoelectron emission, the threshold frequency is defined as the minimum frequency at which field emission begins.

   Correct Option: A

   In photoelectron emission, the threshold frequency is defined as the minimum frequency at which field emission begins.

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179. Schottky effect describes:

1. 1. effect of intensive electric field on the rate of electron emission from a cathode

   
   
   

   2. current in temperature limited region

   
   
   

   3. current in space charge region

   
   
   

   4. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   Schottky effect describes the effect of intensive electric field on the rate of electron emission from a cathode.

   Correct Option: A

   Schottky effect describes the effect of intensive electric field on the rate of electron emission from a cathode.

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180. Figure given below represents:
     
     
     

1. 1. Paramagnetic

   
   
   

   2. Diamagnetic

   
   
   

   3. Ferrimagnetic

   
   
   

   4. Antiferromagnetic

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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