Digital Logic Circuits and Discrete Mathematical Structures Topic Wise Pyq

81. What is the Hamming distance between 1101 and 110?
1101 और 110 के बीच Hamming distance क्या है?
(DSSSB PGT C.S. Male 27.07.2018 Shift-II)
A. 2
B. 3
C. 4
D. 0

Correct Answer: B

Explanation (EN): Write both in equal length: 1101 0110 Now compare bit by bit: 1 and 0 → different 1 and 1 → same 0 and 1 → different 1 and 0 → different Total differing positions = 3 So Hamming distance = 3

Explanation (HI): दोनों को समान लंबाई में लिखते हैं: 1101 0110 अब bit by bit तुलना करें: 1 और 0 → अलग 1 और 1 → समान 0 और 1 → अलग 1 और 0 → अलग कुल अलग स्थान = 3 अतः Hamming distance = 3

82. How will (0.10101)₂ be represented in normalized scientific notation?
(0.10101)₂ को normalized scientific notation में कैसे लिखेंगे?
(DSSSB PGT C.S. Male 27.07.2018 Shift-II)
A. 0.010101 × 2¹
B. 0.10101 × 2⁰
C. 1.0101 × 2⁻¹
D. 10.101 × 2⁻²

Correct Answer: C

Explanation (EN): Normalized binary scientific notation requires one non-zero digit before the binary point. (0.10101)₂ can be written as 1.0101 × 2⁻¹ because the binary point moves one place to the right, so exponent is −1.

Explanation (HI): Normalized binary scientific notation में binary point के पहले एक non-zero digit होना चाहिए। (0.10101)₂ को 1.0101 × 2⁻¹ लिखा जाता है क्योंकि binary point एक स्थान दाईं ओर गया है, इसलिए exponent −1 होगा।

83. Which of the following is the base-4 representation of decimal number 213?
Decimal संख्या 213 का base-4 representation क्या है?
(DSSSB PGT C.S. Male 27.07.2018 Shift-II)
A. (1111)₄
B. (3113)₄
C. (3133)₄
D. (3111)₄

Correct Answer: D

Explanation (EN): Convert 213 to base 4 by repeated division: 213 ÷ 4 = 53 remainder 1 53 ÷ 4 = 13 remainder 1 13 ÷ 4 = 3 remainder 1 3 ÷ 4 = 0 remainder 3 Reading remainders from bottom to top gives 3111₄

Explanation (HI): 213 को 4 से बार-बार भाग दें: 213 ÷ 4 = 53 शेष 1 53 ÷ 4 = 13 शेष 1 13 ÷ 4 = 3 शेष 1 3 ÷ 4 = 0 शेष 3 शेषों को नीचे से ऊपर पढ़ने पर उत्तर 3111₄ मिलेगा।

84. What is the 15's complement of hexadecimal number (C00D0)₁₆ ?
Hexadecimal संख्या (C00D0)₁₆ का 15's complement क्या है?
(DSSSB PGT C.S. Male 27.07.2018 Shift-II)
A. (2FF3F)₁₆
B. (3FF2F)₁₆
C. (3EE2E)₁₆
D. (2EE3E)₁₆

Correct Answer: B

Explanation (EN): 15's complement in hexadecimal means subtract each digit from F: F − C = 3 F − 0 = F F − 0 = F F − D = 2 F − 0 = F So answer = (3FF2F)₁₆

Explanation (HI): Hexadecimal में 15's complement निकालने के लिए हर digit को F में से घटाते हैं: F − C = 3 F − 0 = F F − 0 = F F − D = 2 F − 0 = F अतः उत्तर = (3FF2F)₁₆

85. What is the 10's complement of decimal number 20100?
Decimal संख्या 20100 का 10's complement क्या है?
(DSSSB PGT C.S. Male 27.07.2018 Shift-II)
A. 79899
B. 89999
C. 79900
D. 79800

Correct Answer: C

Explanation (EN): First find 9's complement: 99999 − 20100 = 79899 Now add 1 to get 10's complement: 79899 + 1 = 79900

Explanation (HI): पहले 9's complement निकालते हैं: 99999 − 20100 = 79899 अब 1 जोड़कर 10's complement मिलेगा: 79899 + 1 = 79900

86. If (1101)x = (241)₁₆, then x = ?
यदि (1101)x = (241)₁₆, तो x का मान क्या है?
(DSSSB PGT C.S. Male 27.07.2018 Shift-II)
A. 2
B. 4
C. 8
D. 10

Correct Answer: C

Explanation (EN): Convert (241)₁₆ to decimal: = 2×16² + 4×16 + 1 = 512 + 64 + 1 = 577 Now, (1101)x = x³ + x² + 1 So, x³ + x² + 1 = 577 x³ + x² = 576 Try x = 8: 8³ + 8² = 512 + 64 = 576 So, x = 8

Explanation (HI): (241)₁₆ को decimal में बदलें: = 577 अब, (1101)x = x³ + x² + 1 अतः, x³ + x² + 1 = 577 x³ + x² = 576 x = 8 रखने पर: 8³ + 8² = 512 + 64 = 576 इसलिए x = 8

87. If (12?07)₈ = (1010110000111)₂, then what is the missing digit?
यदि (12?07)₈ = (1010110000111)₂, तो missing digit क्या है?
(DSSSB PGT C.S. Male 27.07.2018 Shift-II)
A. 5
B. 6
C. 7
D. 8

Correct Answer: B

Explanation (EN): Convert the binary number to decimal: (1010110000111)₂ = 5511 Now write octal expression in decimal: (12?07)₈ = 1×8⁴ + 2×8³ + ?×8² + 0×8 + 7 = 4096 + 1024 + 64? + 7 = 5127 + 64? Equate: 5127 + 64? = 5511 64? = 384 ? = 6

Explanation (HI): दिए गए binary को decimal में बदलने पर मान 5511 मिलता है। अब (12?07)₈ को decimal में लिखें: = 1×8⁴ + 2×8³ + ?×8² + 0×8 + 7 = 5127 + 64? अब बराबर रखें: 5127 + 64? = 5511 64? = 384 ? = 6 अतः missing digit 6 है।

88. Considering 2's complement representation, what is decimal value of 10000000 in 8-bit register?
2's complement representation में 8-bit register content 10000000 का decimal value क्या है?
(DSSSB PGT C.S. Male 27.07.2018 Shift-II)
A. −0
B. 0
C. 128
D. −128

Correct Answer: D

Explanation (EN): In 8-bit 2's complement, range is −128 to +127. The pattern 10000000 represents the smallest value, which is −128.

Explanation (HI): 8-bit 2's complement में range −128 से +127 तक होती है। Pattern 10000000 सबसे छोटी संख्या को दर्शाता है, जो −128 है।

89. Identify missing digits: (1010?)₂ + (?7)₈ = (24)₁₆
Missing digits ज्ञात कीजिए: (1010?)₂ + (?7)₈ = (24)₁₆
(DSSSB PGT C.S. Male 27.07.2018 Shift-II)
A. 1,2
B. 1,1
C. 1,6
D. 0,1

Correct Answer: B

Explanation (EN): Convert each term to decimal: (1010x)₂ = 1×2⁴ + 0×2³ + 1×2² + 0×2 + x = 16 + 4 + x = 20 + x (y7)₈ = 8y + 7 (24)₁₆ = 2×16 + 4 = 36 Now, (20 + x) + (8y + 7) = 36 x + 8y = 9 Try options: x = 1, y = 1 gives 1 + 8 = 9 So missing digits are 1, 1

Explanation (HI): हर संख्या को decimal में बदलते हैं: (1010x)₂ = 20 + x (y7)₈ = 8y + 7 (24)₁₆ = 36 अब, (20 + x) + (8y + 7) = 36 x + 8y = 9 विकल्प जाँचने पर x = 1, y = 1 सही बैठता है। अतः missing digits 1, 1 हैं।

90. Which of the following is the 2's complement of (101100)₂ ?
(101100)₂ का 2's complement कौन-सा है?
(DSSSB PGT C.S. Male 27.07.2018 Shift-II)
A. (010011)₂
B. (101111)₂
C. (010100)₂
D. (111100)₂

Correct Answer: C

Explanation (EN): First find 1's complement of 101100: 010011 Now add 1: 010011 + 1 = 010100

Explanation (HI): पहले 101100 का 1's complement लें: 010011 अब 1 जोड़ें: 010011 + 1 = 010100