The output of an XNOR gate will be high when ?

A. The input logic levels are the same

B. One input is high and the other is low

Computer · Introduction to Computing · page 2 of 13

Number Systems & Digital MCQs with Answers

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Number Systems & Digital Logic MCQs (11–20)

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Past paper MCQs in this chapter · See all past papers

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11.
A logic gate has four inputs, its possible input combination will be _?
Correct Answer: B. 16
One-liner
A logic gate with four inputs has 16 possible input combinations, calculated as 2^4.
12.
The output of an XNOR gate will be high when ?
Correct Answer: A. The input logic levels are the same
One-liner
The output of an XNOR gate is high when the input logic levels are the same (both 0 or both 1).
13.
Past Paper MCQ
Binary coded numbers are represented using which digits?
Correct Answer: D. 0 and 1
One-liner
Binary coded numbers are represented using only two digits: 0 and 1.
14.
The Boolean expression of an OR gate is ?
Correct Answer: A. A + B
One-liner
The Boolean expression of an OR gate is A + B, where the "+" symbol represents the logical addition (OR) operation.
15.
The number of LED segments used in a calculator display?
Correct Answer: B. 7
One-liner
A calculator display uses a 7-segment LED arrangement to represent digits.
16.
A NAND gate is a combination of an?
Correct Answer: C. AND gate and NOT gate
One-liner
A NAND gate is a combination of an AND gate and NOT gate, meaning it performs AND operation followed by negation.
17.
A transistor consists of how many junctions?
Correct Answer: C. Two
One-liner
A transistor consists of two PN junctions.
18.
Which gate represents a series gate?
Correct Answer: C. AND gate
One-liner
The AND gate represents a series gate because it requires all inputs to be true (like switches connected in series) to produce a high output.
19.
In a number system with base 2, the number of digits used are
Correct Answer: C. 2
One-liner
In a base-2 (binary) number system, exactly 2 digits are used: 0 and 1.
20.
What does a Half Adder do when both inputs A = 1 and B = 1?
Correct Answer: A. Sum = 0, Carry = 1
One-liner
When both inputs are 1, a Half Adder produces Sum = 0, Carry = 1.

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Number Systems & Digital MCQs with Answers

Number Systems & Digital Logic MCQs (11–20)

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