🔥 MASTER PRACTICE SET – 50 MCQs
(One-Stop Complete Preparation)
🔢 SECTION A: NUMBER SYSTEM – COMPLETE CONVERSIONS (25 MCQs)
Q1. Convert the binary number
(101101)2(101101)_2(101101)2
into decimal.
A. 43
B. 44
C. 45
D. 46
Answer: C
Explanation: 1⋅25+0⋅24+1⋅23+1⋅22+0⋅21+1⋅20=32+8+4+1=451·2^5 + 0·2^4 + 1·2^3 + 1·2^2 + 0·2^1 + 1·2^0 = 32 + 8 + 4 + 1 = 451⋅25+0⋅24+1⋅23+1⋅22+0⋅21+1⋅20=32+8+4+1=45
Q2. Convert the octal number
(745)8(745)_8(745)8
into decimal.
A. 485
B. 489
C. 493
D. 501
Answer: B
Explanation: 7⋅82+4⋅81+5⋅80=448+32+5=4897·8^2 + 4·8^1 + 5·8^0 = 448 + 32 + 5 = 4897⋅82+4⋅81+5⋅80=448+32+5=489
Q3. Convert the hexadecimal number
(9C)16(9C)_{16}(9C)16
into decimal.
A. 154
B. 156
C. 158
D. 160
Answer: B
Explanation:
C = 12 9⋅16+12=1569·16 + 12 = 1569⋅16+12=156
Q4. Convert the decimal number
(512)10(512)_{10}(512)10
into binary.
A. 100000000
B. 1000000000
C. 111111111
D. 110000000
Answer: B
Explanation: 512=29⇒1 followed by 9 zeros512 = 2^9 \Rightarrow 1\text{ followed by 9 zeros}512=29⇒1 followed by 9 zeros
Q5. Convert the binary number
(1101101)2(1101101)_2(1101101)2
into octal.
A. 155
B. 165
C. 175
D. 145
Answer: A
Explanation: 001 101 101⇒1 5 5001\;101\;101 \Rightarrow 1\;5\;5001101101⇒155
Q6. Convert the binary number
(10101111)2(10101111)_2(10101111)2
into hexadecimal.
A. AF
B. BF
C. 9F
D. CF
Answer: A
Explanation: 1010=A, 1111=F1010 = A,\;1111 = F1010=A,1111=F
Q7. Convert the hexadecimal number
(3A)16(3A)_{16}(3A)16
into binary.
A. 00111010
B. 00110110
C. 00111100
D. 00101010
Answer: A
Explanation:
3 → 0011
A → 1010
Q8. Convert the octal number
(57)8(57)_8(57)8
into binary.
A. 101111
B. 110101
C. 111001
D. 101011
Answer: A
Explanation:
5 → 101
7 → 111
Q9. Convert the binary fraction
(0.101)2(0.101)_2(0.101)2
into decimal.
A. 0.5
B. 0.625
C. 0.75
D. 0.875
Answer: B
Explanation: 1⋅2−1+0⋅2−2+1⋅2−3=0.5+0+0.125=0.6251·2^{-1} + 0·2^{-2} + 1·2^{-3} = 0.5 + 0 + 0.125 = 0.6251⋅2−1+0⋅2−2+1⋅2−3=0.5+0+0.125=0.625
Q10. Convert the decimal fraction
(0.625)10(0.625)_{10}(0.625)10
into binary.
A. 0.101
B. 0.110
C. 0.111
D. 0.100
Answer: A
Explanation:
Repeated multiplication by 2 gives 0.101₂
Q11. How many bits are required to represent
(FFFF)_{16} \] ? A. 8 B. 12 C. 16 D. 20 **Answer:** C **Explanation:** 1 hex digit = 4 bits \[ 4×4 = 16
Q12. The decimal equivalent of
(11111111)2(11111111)_2(11111111)2
is:
A. 254
B. 255
C. 256
D. 257
Answer: B
Explanation: 28−1=2552^8 – 1 = 25528−1=255
Q13. Convert
(100100)2(100100)_2(100100)2
into decimal.
A. 34
B. 36
C. 38
D. 40
Answer: B
Q14. Convert
(64)10(64)_{10}(64)10
into octal.
A. 80
B. 90
C. 100
D. 110
Answer: C
Q15. One octal digit is equivalent to how many binary bits?
A. 2
B. 3
C. 4
D. 8
Answer: B
Q16. Convert
(1A3)16(1A3)_{16}(1A3)16
into decimal.
A. 418
B. 419
C. 420
D. 421
Answer: C
Q17. Which conversion uses repeated division method?
A. Binary → Decimal
B. Decimal → Binary
C. Binary → Hexadecimal
D. Octal → Binary
Answer: B
Q18. The MSB of a binary number has:
A. Least weight
B. Zero weight
C. Highest weight
D. Constant value
Answer: C
Q19. Convert
(256)10(256)_{10}(256)10
into hexadecimal.
A. 80
B. 100
C. FF
D. 110
Answer: B
Q20. Convert the binary number
(111000)2(111000)_2(111000)2
into octal.
A. 70
B. 72
C. 74
D. 76
Answer: C
Q21. Convert the decimal number
(1024)10(1024)_{10}(1024)10
into binary.
A. 1000000000
B. 10000000000
C. 1111111111
D. 11000000000
Answer: B
Q22. Convert the binary fraction
(0.11)2(0.11)_2(0.11)2
into decimal.
A. 0.5
B. 0.75
C. 0.625
D. 0.875
Answer: B
Q23. Convert the octal number
(377)8(377)_8(377)8
into decimal.
A. 247
B. 255
C. 263
D. 271
Answer: B
Q24. Convert
(FF)16(FF)_{16}(FF)16
into decimal.
A. 254
B. 255
C. 256
D. 257
Answer: B
Q25. Binary subtraction is performed in base:
A. 10
B. 8
C. 2
D. 16
Answer: C
⚙️ SECTION B: LOGIC GATES – TRUTH TABLE + EQUATION (25 MCQs)
Q26. Identify the gate represented by
Y=AB‾+A‾BY = A\overline{B} + \overline{A}BY=AB+AB
A. AND
B. OR
C. XOR
D. XNOR
Answer: C
Explanation:
This is the standard Boolean equation of XOR gate.
Q27. Identify the gate represented by
Y=(A+B)′Y = (A + B)’Y=(A+B)′
A. NAND
B. NOR
C. AND
D. XOR
Answer: B
Q28. Identify the gate represented by
Y=(A⋅B)′Y = (A·B)’Y=(A⋅B)′
A. AND
B. OR
C. NAND
D. NOR
Answer: C
Q29. For a 2-input AND gate, output = 1 occurs how many times?
A. 0
B. 1
C. 2
D. 3
Answer: B
Q30. For which input does a NOR gate give output 1?
A. 00
B. 01
C. 10
D. 11
Answer: A
Q31. Simplify:
Y=A+A⋅BY = A + A·BY=A+A⋅B
A. AB
B. A
C. A + B
D. B
Answer: B
Q32. Simplify:
Y=A⋅A′Y = A·A’Y=A⋅A′
A. 1
B. A
C. A’
D. 0
Answer: D
Q33. According to De Morgan’s theorem:
(A+B)′=(A + B)’ =(A+B)′=
A. A’ + B’
B. A’B’
C. AB
D. (AB)’
Answer: B
Q34. Output of XOR gate is 1 when:
A. Inputs are same
B. Inputs are different
C. All inputs are 1
D. All inputs are 0
Answer: B
Q35. XNOR gate is also called:
A. Difference detector
B. Equality detector
C. Inverter
D. Buffer
Answer: B
Q36. NAND gate is an inverted form of:
A. OR
B. AND
C. XOR
D. NOR
Answer: B
Q37. NOR gate is an inverted form of:
A. AND
B. OR
C. XOR
D. NAND
Answer: B
Q38. Which gate behaves as NOT gate when inputs are shorted?
A. AND
B. OR
C. NAND
D. XOR
Answer: C
Q39. Number of input combinations in a 3-input gate is:
A. 6
B. 8
C. 10
D. 16
Answer: B
Q40. Half adder SUM output is obtained using:
A. AND
B. OR
C. XOR
D. NAND
Answer: C
Q41. Half adder CARRY output is obtained using:
A. AND
B. OR
C. XOR
D. NOR
Answer: A
Q42. Full adder has how many inputs?
A. 2
B. 3
C. 4
D. 5
Answer: B
Q43. Output of
(A⊕B)′(A ⊕ B)'(A⊕B)′
is equivalent to which gate?
A. XOR
B. XNOR
C. NAND
D. NOR
Answer: B
Q44. Truth table of which gate has output = 1 exactly twice?
A. AND
B. OR
C. XOR
D. NOR
Answer: C
Q45. Buffer gate is used for:
A. Inversion
B. Isolation
C. Addition
D. Comparison
Answer: B
Q46. Universal gates are:
A. AND, OR
B. OR, NOT
C. NAND, NOR
D. XOR, XNOR
Answer: C
Q47. Output of NOR gate for inputs (1,1) is:
A. 0
B. 1
C. Undefined
D. High
Answer: A
Q48. Which gate is used in parity checking?
A. AND
B. OR
C. XOR
D. NAND
Answer: C
Q49. Boolean algebra was introduced by:
A. Newton
B. Shannon
C. Boole
D. Maxwell
Answer: C
Q50. Logic gates are the basic building blocks of:
A. Analog systems
B. Mechanical systems
C. Digital systems
D. Optical systems
Answer: C
