Digital Logic & Number representation

Question 11

The minterm expansion of f(P, Q, R) = PQ + QR\' + PR\' is

• m2 + m4 + m6 + m7
• m0 + m1 + m3 + m5
• m0 + m1 + m6 + m7
• m2 + m3 + m4 + m5

Question 12

The Boolean expression for the output \'f\' of the multiplexer shown below is:

[caption width="800"] [/caption]

• (P(XOR)Q(XOR)R)\'

• P(XOR)Q(XOR)R

• (P+Q+R)\'

• P+Q+R

Question 13

What is the Boolean expression for the output f of the combinational logic circuit of NOR gates given below?

• (Q+R)\'
• (P+Q)\'
• (P+R)
• (P+Q+R)\'

Question 14

In the sequential circuit shown below,if the initial value of the output Q1Q0 is 00,what are the next four values of Q1Q0? 

[caption width="800"] [/caption]

• 11, 10, 01, 00

• 10, 11, 01, 00

• 10, 00, 01, 11

• 11, 10, 00, 01

Question 15

What is the minimum number of gates required to implement the Boolean function (AB+C)if we have to use only 2-input NOR gates?

• 2
• 3
• 4
• 5

Question 16

Let r denote number system radix. The only value(s) of r that satisfy the equation 

• decimal 10
• decimal 11
• decimal 10 and 11
• any value > 2

Question 17

In the Karnaugh map shown below, X denotes a don\'t care term. What is the minimal form of the function represented by the Karnaugh map?

A)   


B) 

C) 

D)  

• A

• B

• C

• D

Question 18

Given f₁, f₃ and f in canonical sum of products form (in decimal) for the circuit

A) m(4, 6)

B) m(4, 8)

C) m(6, 8)

D) m(4, 6, 8)

• A
• B
• C
• D

Question 19

If P, Q, R are Boolean variables, then (P + Q\')(PQ\' + PR)(P\'R\' + Q\') simplifies

• PQ\'
• PR\'
• PQ\' + R
• PR\'\' + Q

Question 20

How many 3-to-8 line decoders with an enable input are needed to construct a 6-to-64 line decoder without using any other logic gates?

• 7
• 8
• 9
• 10