PLTW DIGITAL ELECTRONICS (DE) EXAM
QUESTIONS AND CORRECT ANSWERS (VERIFIED
ANSWERS) Q&A 2027 |INSTANT DOWNLOAD PDF
1. Which number system is most commonly used in digital
electronics to represent data internally?
A. Decimal
B. Binary
C. Octal only
D. Roman numeral
Answer: B. Binary
Rationale: Digital circuits use two discrete logic states,
commonly represented as 0 and 1, making the binary system
fundamental to digital electronics.
2. How many different values can one binary bit represent?
A. 1
B. 2
C. 8
D. 16
Answer: B. 2
Rationale: A bit can have one of two states: 0 or 1.
,3. What is the decimal equivalent of binary 1010?
A. 8
B. 9
C. 10
D. 12
Answer: C. 10
Rationale: 10102=8+2=10101010_2 = 8 + 2 = 10_{10}.
4. What is the binary representation of decimal 15?
A. 1010
B. 1100
C. 1110
D. 1111
Answer: D. 1111
Rationale: Decimal 15 equals 8+4+2+18+4+2+1, producing
binary 1111.
5. Which logic state generally represents FALSE in digital logic?
A. 0
B. 1
C. 2
D. HIGH only
,Answer: A. 0
Rationale: In positive logic, 0 represents LOW or FALSE and 1
represents HIGH or TRUE.
6. Which logic gate produces HIGH only when all of its inputs
are HIGH?
A. OR
B. NOT
C. AND
D. XOR
Answer: C. AND
Rationale: An AND gate outputs 1 only when every input is 1.
7. Which gate produces HIGH when at least one input is HIGH?
A. AND
B. OR
C. NOT
D. NAND
Answer: B. OR
Rationale: An OR gate produces 1 whenever one or more
inputs are 1.
8. What is the primary function of a NOT gate?
, A. Add binary numbers
B. Invert the input
C. Store data
D. Multiply signals
Answer: B. Invert the input
Rationale: A NOT gate changes 0 to 1 and 1 to 0.
9. Which gate is equivalent to an AND gate followed by a NOT
gate?
A. NOR
B. XOR
C. NAND
D. XNOR
Answer: C. NAND
Rationale: NAND means NOT-AND; its output is the inverse of
the AND operation.
10. Which gate is equivalent to an OR gate followed by a NOT
gate?
A. NAND
B. NOR
C. XOR
D. AND
QUESTIONS AND CORRECT ANSWERS (VERIFIED
ANSWERS) Q&A 2027 |INSTANT DOWNLOAD PDF
1. Which number system is most commonly used in digital
electronics to represent data internally?
A. Decimal
B. Binary
C. Octal only
D. Roman numeral
Answer: B. Binary
Rationale: Digital circuits use two discrete logic states,
commonly represented as 0 and 1, making the binary system
fundamental to digital electronics.
2. How many different values can one binary bit represent?
A. 1
B. 2
C. 8
D. 16
Answer: B. 2
Rationale: A bit can have one of two states: 0 or 1.
,3. What is the decimal equivalent of binary 1010?
A. 8
B. 9
C. 10
D. 12
Answer: C. 10
Rationale: 10102=8+2=10101010_2 = 8 + 2 = 10_{10}.
4. What is the binary representation of decimal 15?
A. 1010
B. 1100
C. 1110
D. 1111
Answer: D. 1111
Rationale: Decimal 15 equals 8+4+2+18+4+2+1, producing
binary 1111.
5. Which logic state generally represents FALSE in digital logic?
A. 0
B. 1
C. 2
D. HIGH only
,Answer: A. 0
Rationale: In positive logic, 0 represents LOW or FALSE and 1
represents HIGH or TRUE.
6. Which logic gate produces HIGH only when all of its inputs
are HIGH?
A. OR
B. NOT
C. AND
D. XOR
Answer: C. AND
Rationale: An AND gate outputs 1 only when every input is 1.
7. Which gate produces HIGH when at least one input is HIGH?
A. AND
B. OR
C. NOT
D. NAND
Answer: B. OR
Rationale: An OR gate produces 1 whenever one or more
inputs are 1.
8. What is the primary function of a NOT gate?
, A. Add binary numbers
B. Invert the input
C. Store data
D. Multiply signals
Answer: B. Invert the input
Rationale: A NOT gate changes 0 to 1 and 1 to 0.
9. Which gate is equivalent to an AND gate followed by a NOT
gate?
A. NOR
B. XOR
C. NAND
D. XNOR
Answer: C. NAND
Rationale: NAND means NOT-AND; its output is the inverse of
the AND operation.
10. Which gate is equivalent to an OR gate followed by a NOT
gate?
A. NAND
B. NOR
C. XOR
D. AND
