136. The shift register shown below is initially loaded with the bit pattern 1010. Subsequently the shift register is clocked, and with each clock pulse the pattern gets shifted by one bit position to the right. With each shift, the bit at the serial input is pushed to the left most position (i.e. MSB). After how many clock pulses will the content of the shift register become 1010 again—
     
     
     

1. 1. 3

   
   
   

   2. 7

   
   
   

   3. 11

   
   
   

   4. 15

   
   
   

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   NA

   Correct Option: B

   NA

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137. Shifting a register to the left by one bit position is equivalent to (in binary code)—

1. 1. Division by 2

   
   
   

   2. Multiplication by 2

   
   
   

   3. Addition of 2

   
   
   

   4. Subtraction of 2

   
   
   

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   NA

   Correct Option: B

   NA

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138. The Boolean expression X = AB + CD represents—

1. 1. Two ORs ANDed together

   
   
   

   2. A 4-input AND gate

   
   
   

   3. Two ANDs ORed together

   
   
   

   4. An exclusive OR

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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139. According to Demorgan’s theorem the following equality (s) are correct—

1. 1. AB = A + B

   
   
   

   2. XYZ = X + Y + Z

   
   
   

   3. A + B + C = A B C

   
   
   

   4. All of these

   
   
   

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   AB = A + B
   XYZ = X + Y + Z
   A + B + C = A B C

   Correct Option: D

   AB = A + B
   XYZ = X + Y + Z
   A + B + C = A B C

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140. Which of the following rules state that if one input of an AND gate is always 1, the output is equal to the other input?

1. 1. A + 1 = 1

   
   
   

   2. A + A = A

   
   
   

   3. A·A = A

   
   
   

   4. A·1 = A

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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