Competitive Exams : Computer Awareness - Mix (Set 3)

Question 1

If the decimal number 133 is represented in 8-bit 2's complement form, what is its binary representation?

Accepted Answer

C) Not representable in 8-bit 2's complement

Answer

A) 01000101

Answer

B) 10000101

Answer

D) 01000101

Question 2

What is the decimal equivalent of the binary number $1101.101_2$?

Accepted Answer

B) 13.625

Answer

A) 13.625

Answer

C) 12.525

Answer

D) 14.75

Question 3

Perform the binary addition: $10110_2 + 1101_2$.

Accepted Answer

A) 100011

Answer

B) 101011

Answer

C) 110001

Answer

D) 100101

Question 4

Using 8-bit 2's complement, what is the result of $25 - 40$?

Accepted Answer

D) 11110001

Answer

A) 00001111

Answer

B) 11110001

Answer

C) 00001001

Question 5

Convert the hexadecimal number $3F.C_{16}$ to its binary equivalent.

Accepted Answer

B) $00111111.1100_2$

Answer

A) $00111110.1100_2$

Answer

C) $00111111.1010_2$

Answer

D) $00111100.1100_2$

Question 6

What is the result of binary multiplication: $1101_2 imes 101_2$?

Accepted Answer

C) $1000001_2$

Answer

A) $1000001_2$

Answer

B) $1001001_2$

Answer

D) $1111101_2$

Question 7

A 4-bit binary number is used to represent signed integers using 1's complement. What is the maximum positive value that can be represented?

Accepted Answer

A) +7

Answer

B) +15

Answer

C) +8

Answer

D) +14

Question 8

Which of the following is the Gray code equivalent of the binary number $10110_2$?

Accepted Answer

B) $11101_{Gray}$

Answer

A) $10110_{Gray}$

Answer

C) $01001_{Gray}$

Answer

D) $11001_{Gray}$

Question 9

What is the BCD (Binary Coded Decimal) representation of the decimal number 69?

Accepted Answer

D) $01101001_{BCD}$

Answer

A) $01101001_2$

Answer

B) $1000101_2$

Answer

C) $0110001001_2$

Question 10

If a computer system uses signed magnitude representation with 7 bits for magnitude and 1 bit for sign, what is the range of integers it can represent?

Accepted Answer

A) -127 to +127

Answer

B) -128 to +127

Answer

C) -255 to +255

Answer

D) 0 to 255

Question 11

Which of the following Boolean expressions is equivalent to $(A + B)(A + C)$?

Accepted Answer

B) $A + BC$

Answer

A) $A \cdot B + C$

Answer

C) $A + B + C$

Answer

D) $(A+B)C$

Question 12

A circuit produces an output of HIGH only when all its inputs are LOW. Which basic logic gate implements this behavior?

Accepted Answer

A) NOR gate

Answer

B) NAND gate

Answer

C) OR gate

Answer

D) AND gate

Question 13

Simplify the Boolean expression $X = AB + A(B+C) + B(B+C)$.

Accepted Answer

D) $A+B+C$

Answer

A) $A+B$

Answer

B) $B+AC$

Answer

C) $A+C$

Question 14

Which of the following gates is considered a universal gate, meaning any other logic gate can be constructed from it?

Accepted Answer

C) NAND gate

Answer

A) XOR gate

Answer

B) OR gate

Answer

D) AND gate

Question 15

Using only NOR gates, how would you construct an AND gate?

Accepted Answer

A) Connect the outputs of two NOR gates (each with one input tied to a specific input variable) to a third NOR gate.

Answer

B) Connect the inputs of two NOR gates to an inverter (NOT gate).

Answer

C) Connect two NOR gates in series.

Answer

D) Simply use a single NOR gate.

Question 16

Given the Boolean expression $F = (A+B)(\overline{A}+C)$, which of the following is its simplified SOP (Sum of Products) form?

Accepted Answer

B) $A \cdot C + \overline{A} \cdot B + B \cdot C$

Answer

A) $A \cdot C + \overline{A} \cdot B$

Answer

C) $A \cdot B + C$

Answer

D) $A+B+C$

Question 17

Consider a circuit with inputs A, B, and C. The output Z is HIGH if and only if A is HIGH, OR B is LOW AND C is HIGH.

Which Boolean expression correctly describes the output Z?

Accepted Answer

A) $Z = A + (\overline{B} \cdot C)$

Answer

B) $Z = A \cdot (\overline{B} + C)$

Answer

C) $Z = \overline{A} + (B \cdot \overline{C})$

Answer

D) $Z = (A \cdot B) + (\overline{C})$

Question 18

What is the output of a 2-input XOR gate if its inputs are $A=1$ and $B=1$?

Accepted Answer

C) 0

Answer

A) 1

Answer

B) Undefined

Answer

D) Depends on previous state

Question 19

Which of the following statements is true regarding De Morgan's Theorems?

Accepted Answer

B) $\overline{A \cdot B} = \overline{A} + \overline{B}$

Answer

A) $\overline{A+B} = \overline{A} + \overline{B}$

Answer

C) $A+B = \overline{\overline{A} + \overline{B}}$

Answer

D) $A \cdot B = \overline{A} \cdot \overline{B}$

Question 20

A circuit has inputs $X_1, X_2$ and output $Y$.
If $X_1=0, X_2=0$, then $Y=0$.
If $X_1=0, X_2=1$, then $Y=1$.
If $X_1=1, X_2=0$, then $Y=1$.
If $X_1=1, X_2=1$, then $Y=0$.

Which type of logic gate does this truth table represent?

Accepted Answer

D) XOR gate

Answer

A) AND gate

Answer

B) OR gate

Answer

C) XNOR gate