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MCQOPTIONS
This section includes 66 Mcqs, each offering curated multiple-choice questions to sharpen your Digital Logic Design knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
In IEEE floating point representation, the hexadecimal number 0xC0000000 corresponds to |
| A. | –3.0 |
| B. | –1.0 |
| C. | –4.0 |
| D. | –2.0 |
| Answer» E. | |
| 2. |
Original ASCII coding scheme uses ______ bits for coding 128 different characters. |
| A. | 6 |
| B. | 7 |
| C. | 8 |
| D. | 16 |
| Answer» C. 8 | |
| 3. |
According to Boolean law: \(\overline {\bar A}\) = ? |
| A. | 0 |
| B. | A |
| C. | \(\overline {\bar A}\) |
| D. | 1 |
| Answer» C. \(\overline {\bar A}\) | |
| 4. |
Consider the following gate networkWhich one of the following gates is redundant? |
| A. | Gate No.1 |
| B. | Gate No.2 |
| C. | Gate No.3 |
| D. | Gate No.4 |
| Answer» C. Gate No.3 | |
| 5. |
Express -39 in 8-bit 2's complement form. |
| A. | 11011001 |
| B. | 01101010 |
| C. | 01000101 |
| D. | 10101001 |
| Answer» B. 01101010 | |
| 6. |
If the numerical value of a 2-byte unsigned integer on a little endian computer is 255 more than that on a big endian computer, which of the following choices represent(s) the unsigned integer on a little endian computer? |
| A. | 0x0001 |
| B. | 0x6665 |
| C. | 0x0100 |
| D. | 0x4243 |
| Answer» C. 0x0100 | |
| 7. |
Let m = (313)4 and n = (322)4. Find the base 4 expansion of m + n. |
| A. | (635)4 |
| B. | (32312)4 |
| C. | (21323)4 |
| D. | (1301)4 |
| Answer» E. | |
| 8. |
Given the function F = P’ + QR, where F is a function in three Boolean variables P, Q and R and P’ = !P, consider the following statements.(S1) F = ∑ (4, 5, 6)(S2) F = ∑ (0, 1, 2, 3, 7)(S3) F = Π (4, 5, 6)(S4) F = Π (0, 1, 2, 3, 7)Which of the following is true? |
| A. | (S1) – False, (S2) – True, (S3) – True, (S4) - False |
| B. | (S1) – True, (S2) – False, (S3) – False, (S4) - True |
| C. | (S1) – False, (S2) – False, (S3) – True, (S4) - True |
| D. | (S1) – True, (S2) – True, (S3) – False, (S4) - False |
| Answer» B. (S1) – True, (S2) – False, (S3) – False, (S4) - True | |
| 9. |
Consider the following Boolean expression for F:F(P, Q, R, S) = PQ + P̅QR + P̅QR̅SThe minimal sum-of-products form of F is |
| A. | PQ + QR + QS |
| B. | P + Q + R + S |
| C. | P̅ + Q̅ + R̅ + S̅ |
| D. | P̅R + P̅R̅S + P |
| Answer» B. P + Q + R + S | |
| 10. |
consider the following Boolean expression for F over two variables P and Q:F(P, Q) = ((1 ⊕ P) ⊕(P⊕Q)) ⊕((P⊕Q) ⊕(Q⊕0) )The equivalent expression for F is |
| A. | P + Q |
| B. | \(\overline {P + Q} \) |
| C. | \(P \oplus Q\) |
| D. | \(\overline {P \oplus Q} \) |
| Answer» E. | |
| 11. |
Exclusive OR(XOR) is a special gate whose output is 1 only if: |
| A. | All inputs are 0 |
| B. | All inputs are 1 |
| C. | Odd numbers of inputs are 1 |
| D. | Even number of inputs are 1 |
| Answer» D. Even number of inputs are 1 | |
| 12. |
Consider the following Boolean expression.\(F = (X + Y + Z)(\overline X + Y)(\overline Y + Z)\)Which of the following Boolean expressions is/are equivalent to \(\overline F\) (complement of F)? |
| A. | \((\overline X + \overline Y + \overline Z )(X + \overline Y )(Y + \overline Z )\) |
| B. | \(X\overline Y + \overline Z\) |
| C. | \(X\overline Y + Y\overline Z + \overline X \overline Y \overline Z \) |
| D. | \((X + \overline Z ) . (\overline Y + \overline Z )\) |
| Answer» C. \(X\overline Y + Y\overline Z + \overline X \overline Y \overline Z \) | |
| 13. |
Consider the unsigned 8-bit fixed point binary number representation below, b7 b6 b5 b4 b3 . b2 b1 b0 where the position of the binary point is between b3 and b2. Assume b7 is the most significant bit. Some of the decimal numbers listed below cannot be represented exactly in the above representation:(i) 31.500 (ii) 0.875 (iii) 12.100 (iv) 3.001Which one of the following statements is true? |
| A. | None of (i), (ii), (iii), (iv) can be exactly represented |
| B. | Only (ii) cannot be exactly represented |
| C. | Only (iii) and (iv) cannot be exactly represented |
| D. | Only (i) and (ii) cannot be exactly represented |
| Answer» D. Only (i) and (ii) cannot be exactly represented | |
| 14. |
_______ is a function for which the number of minterms and number of maxterms are same. |
| A. | Boolean |
| B. | Universal |
| C. | Self dual |
| D. | Neutral |
| Answer» E. | |
| 15. |
How many gate(S) would be required to implement the following Boolean expression after simplification?Expression : AC + ABC |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» B. 2 | |
| 16. |
Let the representation of a number in base 3 be 210. What is the hexadecimal representation of the number? |
| A. | 21 |
| B. | 528 |
| C. | D2 |
| D. | 15 |
| Answer» E. | |
| 17. |
Consider the Boolean function z(a, b, c).Which one of the following minterm lists represents the circuit given above? |
| A. | z = ∑ (0, 1, 3, 7) |
| B. | z = ∑ (1, 4, 5, 6, 7) |
| C. | z = ∑ (2, 4, 5, 6, 7) |
| D. | z = ∑ (2, 3, 5) |
| Answer» C. z = ∑ (2, 4, 5, 6, 7) | |
| 18. |
Given f(w, x, y, z) = ∑m (0, 1, 2, 3, 7, 8, 10) + ∑d (5, 6, 11, 15), where d represents the don’t-care condition in Karnaugh maps. Which of the following is a minimum product-of-sums (POS) form of f(w, x, y, z)? |
| A. | f = (w̅ + z̅ )(x̅ + z) |
| B. | f = (w̅ + z)(x + z) |
| C. | f = (w + z)(x̅ + z) |
| D. | f = (w + z̅ )(x̅ + z) |
| Answer» B. f = (w̅ + z)(x + z) | |
| 19. |
For following logic diagram which expression is true? |
| A. | \(\overline {\left( {\overline {A.B} } \right) + \left( {A.B} \right)} \) |
| B. | \(\overline {\left( {\bar A\;.\bar B} \right).\left( {A.B} \right)} \) |
| C. | \(\overline {AB} .AB\) |
| D. | \(\left( {A.B} \right)\left( {\overline {A.B} } \right)\) |
| Answer» C. \(\overline {AB} .AB\) | |
| 20. |
EBCDIC stand for __________ |
| A. | Extended Binary Coded Data Interchange |
| B. | Expanded Binary coded Decimal Interchange Code |
| C. | Extended Binary Coded Decimal Interchange Code |
| D. | Expanded Binary Coded Data Interchange Code |
| Answer» D. Expanded Binary Coded Data Interchange Code | |
| 21. |
Consider Z = X - Y, where X, Y and Z are all in sign-magnitude form. X and Y are each represented in n bits. To avoid overflow, the representation of Z would require a minimum of: |
| A. | n bits |
| B. | n - 1 bits |
| C. | n + 1 bits |
| D. | n + 2 bits |
| Answer» D. n + 2 bits | |
| 22. |
Any set of Boolean operators that is sufficient to represent all Boolean expressions is said to be complete. Which of the following is not complete? |
| A. | {AND, OR} |
| B. | {AND, NOT} |
| C. | {NOT, OR} |
| D. | {NOR} |
| Answer» B. {AND, NOT} | |
| 23. |
If 12A7C16 = X8, then the value of X is |
| A. | 224174 |
| B. | 425174 |
| C. | 6173 |
| D. | 225174 |
| Answer» E. | |
| 24. |
Minimum number of NAND gates required to implement the following binary equation Y = (A̅ + B̅)(C + D) |
| A. | 4 |
| B. | 5 |
| C. | 3 |
| D. | 6 |
| Answer» B. 5 | |
| 25. |
Let, x1 ⊕ x2 ⊕ x3 ⊕ x4 = 0 where x1, x2, x3, x4 are Boolean variables, and ⊕ is the XOR operator.Which one of the following must always is TRUE? |
| A. | x1x2x3x4 = 0 |
| B. | x1x3 + x2 = 0 |
| C. | x̅1 ⊕ x̅3 = x̅2 ⊕ x̅4 |
| D. | x1 + x2 + x3 + x4 = 0 |
| Answer» D. x1 + x2 + x3 + x4 = 0 | |
| 26. |
How many bits are used in the exponent part of IEEE single precision format for the representation of floating - point numbers ? |
| A. | 8 bits |
| B. | 24 bits |
| C. | 16 bits |
| D. | 32 bits |
| Answer» B. 24 bits | |
| 27. |
Consider the following min term expression for F.F (P, Q, R, S) = ∑ 0, 2, 5, 7, 8, 10, 13, 15The min-terms 2, 7, 8 and 13 are ‘do not care’ terms. The minimal sum-of-products form for F is |
| A. | QS̅ + Q̅ S |
| B. | Q̅S̅ + QS |
| C. | Q̅R̅S̅ + Q̅RS̅+ QR̅S + QRS |
| D. | P̅Q̅S̅ + P̅QS + PQS + PQ̅S̅ |
| Answer» C. Q̅R̅S̅ + Q̅RS̅+ QR̅S + QRS | |
| 28. |
For an n-variable Boolean function, the maximum number of prime implicants is |
| A. | 2(n - 1) |
| B. | n/2 |
| C. | 2n |
| D. | 2(n-1) |
| Answer» E. | |
| 29. |
In the standard IEEE 754 single precision floating point representation, there is 1 bit for sign, 23 bits for fraction and 8 bits for exponent. What is the precision in terms of the number of decimal digits? |
| A. | 5 |
| B. | 6 |
| C. | 7 |
| D. | 8 |
| Answer» D. 8 | |
| 30. |
If ABCD is a 4-bit binary number, then what is code generated by the following circuit? |
| A. | BCD code |
| B. | Gray code |
| C. | 8421 code |
| D. | Excess-3 code |
| Answer» C. 8421 code | |
| 31. |
How many different BCD numbers can be stored in 12 switches ? (Assume two position or on-off switches). |
| A. | 212 |
| B. | 212 - 1 |
| C. | 1012 |
| D. | 103 |
| Answer» E. | |
| 32. |
Minimum number of 2 × 1 multiplexers required to realize the following function,f =A̅ B̅ C + A̅ B̅ C̅.Assume that inputs are available only in true form and Boolean a constant 1 and 0 are available. |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 7 |
| Answer» C. 3 | |
| 33. |
A computer uses ternary system instead of the traditional binary system. An n bit string in the binary system will occupy |
| A. | 3 + n ternary digits |
| B. | 2n/3 ternary digits |
| C. | n(log23) ternary digits |
| D. | n(log32) ternary digits |
| Answer» E. | |
| 34. |
Consider the following circuitThe function by the network above is |
| A. | \(\overline {AB} E + EF + \overline {CD} F\) |
| B. | \(\left( {\bar E + AB\bar F} \right)\left( {C + D + \bar F} \right)\) |
| C. | \(\left( {\overline {AB} + E} \right)\left( {\bar E + \bar F} \right)\left( {C + D + \bar F} \right)\) |
| D. | \(\left( {A + B} \right)\bar E + \overline {EF} + CD\bar F\) |
| Answer» C. \(\left( {\overline {AB} + E} \right)\left( {\bar E + \bar F} \right)\left( {C + D + \bar F} \right)\) | |
| 35. |
If w, x, y, z Boolean variables, then which one of the following is INCORRECT? |
| A. | wx + w(x + y) + x(x + y) = x + wy |
| B. | \(\overline {w\bar x\left( {y + \bar z} \right)} + \bar wx = \bar w + x + \;\bar yz\) |
| C. | (wx̅ (y + xz̅ ) + w̅ x̅)y = xy̅ |
| D. | (w + y) (wxy + wyz) = wxy + wyz |
| Answer» D. (w + y) (wxy + wyz) = wxy + wyz | |
| 36. |
BCD stands for ________ . |
| A. | Binary Coded Decimal |
| B. | Binary Code Display |
| C. | Bidirectional Coded Data |
| D. | Binary Coded Data |
| Answer» B. Binary Code Display | |
| 37. |
EBCDIC coding scheme uses ______ bits to code different characters. |
| A. | 4 |
| B. | 8 |
| C. | 16 |
| D. | 32 |
| Answer» C. 16 | |
| 38. |
BCD coding scheme uses _____ bits to code decimal digits. |
| A. | 4 |
| B. | 8 |
| C. | 16 |
| D. | 32 |
| Answer» B. 8 | |
| 39. |
Consider three registers R1, R2 and R3 that store numbers in IEEE-754 single precision floating point format. Assume that R1 and R2 contain the values (in hexadecimal notation) 0x42200000 and 0xC1200000, respectively.If R3 \(= \frac{{R1}}{{R2}},\) what is the value stored in R3? |
| A. | 0x40800000 |
| B. | 0xC0800000 |
| C. | 0x83400000 |
| D. | 0xC85800000 |
| Answer» C. 0x83400000 | |
| 40. |
In a hexadecimal system the radix is: |
| A. | 15 |
| B. | 1 |
| C. | 8 |
| D. | 16 |
| Answer» E. | |
| 41. |
A decimal number has 64 digits. The number of bits needed for its equivalent binary representation is |
| A. | 200 |
| B. | 213 |
| C. | 246 |
| D. | 277 |
| Answer» C. 246 | |
| 42. |
Minterms corresponding to decimal number 15 is |
| A. | ABCD |
| B. | A̅ B̅ C̅ D̅ |
| C. | A + B + C + D |
| D. | A̅ + B̅ + C̅ + D̅ |
| Answer» B. A̅ B̅ C̅ D̅ | |
| 43. |
Let # be a binary operator defined asX # Y = X’ + Y’ where X and Y are Boolean variables.Consider the following two statements.(S1) (P # Q) #R = P# (Q # R)(S2) Q # R = R # QWhich of the following is/are true for the Boolean variables P, Q and R? |
| A. | Only S1 is true |
| B. | Only S2 is true |
| C. | Both S1 and S2 are true |
| D. | Neither S1 nor S2 are true |
| Answer» C. Both S1 and S2 are true | |
| 44. |
How many gate(s) would be required to implement the following boolean expression after simplification?Expression: A’(C’D’ + C’D) + AB(C’D’ + C’D) + AB’C’ |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» B. 2 | |
| 45. |
If (11X1Y)8 = (12C9)16, then the respective values of X and Y are: |
| A. | 1 and 5 |
| B. | 3 and 1 |
| C. | 5 and 7 |
| D. | 7 and 5 |
| Answer» C. 5 and 7 | |
| 46. |
MSB stands for: |
| A. | Maximum significant bit |
| B. | Middle significant bit |
| C. | Most significant bit |
| D. | Measured significant bit |
| Answer» D. Measured significant bit | |
| 47. |
Given, \(\sqrt {{{224}_r}} = {13_r}\) the value of radix r is |
| A. | 10 |
| B. | 8 |
| C. | 6 |
| D. | 5 |
| Answer» E. | |
| 48. |
In 16-bit 2’s complement representation, the decimal number -28 is: |
| A. | 1111 1111 0001 1100 |
| B. | 0000 0000 1110 0100 |
| C. | 1111 1111 1110 0100 |
| D. | 1000 0000 1110 0100 |
| Answer» D. 1000 0000 1110 0100 | |
| 49. |
If x, y, z are Boolean variable then (x + y̅) (x ⋅ y̅ + x ⋅ z) (x̅ ⋅ z + y̅) is equal to: |
| A. | x ⋅ y̅ |
| B. | x ⋅ y̅ + z |
| C. | x ⋅ z̅ |
| D. | none of the options |
| Answer» B. x ⋅ y̅ + z | |
| 50. |
A computer with 32 bit word size uses 2s compliment to represent numbers. The range of integers that can be represented by this computer is |
| A. | –232 to 232 |
| B. | –231 to 232 –1 |
| C. | –231 to 231 –1 |
| D. | –231 –1 to 232 –1 |
| Answer» D. –231 –1 to 232 –1 | |