46. If N_D and N_A are the donar and acceptor concentrations then if N_D > N_A the net impurity concentration is—

1. 1. N_D – N_A

   
   
   

   2. N_D + N_A

   
   
   

   3. N_D

   
   
   

   4. N_A

   
   
   

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   NA

   Correct Option: A

   NA

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47. In a semiconductor, fermi level is proportional to—

1. 1. N

   
   
   

   2. N²

   
   
   

   3. N^2/3

   
   
   

   4. N^3/2

   
   
   

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   NA

   Correct Option: C

   NA

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48. In silicon the concentration of thermally generated electrons at room temperature is of the order of—

1. 1. 10⁸ cm^–3

   
   
   

   2. 10¹⁰ cm^–3

   
   
   

   3. 10¹³ cm^–3

   
   
   

   4. 10¹⁵ cm^–3

   
   
   

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   In silicon the concentration of thermally generated electrons at room temperature is of the order of 10¹⁵ cm^–3.

   Correct Option: D

   In silicon the concentration of thermally generated electrons at room temperature is of the order of 10¹⁵ cm^–3.

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49. What best describes the circuit?
    
    
    

1. 1. Full-wave rectifier

   
   
   

   2. Half-wave rectifier

   
   
   

   3. Clipper

   
   
   

   4. Clamper

   
   
   

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   NA

   Correct Option: A

   NA

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50. Determine I_D.—
    
    
    

1. 1. 0 mA

   
   
   

   2. 1.86 mA

   
   
   

   3. 2.036 mA

   
   
   

   4. 2.143 mA

   
   
   

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1. View Hint View Answer Discuss in Forum

   From the given information, we can make the equivalent circuit as shown below:
   From below (i.e., fig-2) circuit applying KVL
   12–0.7–0.7–I_D × 5.6 kΩ = 0
   or

   ID =	10·4 V	1.86 mA
   	5.6 kΩ

   
   

   Correct Option: B

   From the given information, we can make the equivalent circuit as shown below:
   From below (i.e., fig-2) circuit applying KVL
   12–0.7–0.7–I_D × 5.6 kΩ = 0
   or

   ID =	10·4 V	1.86 mA
   	5.6 kΩ

   
   

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