Paper - II (viii) — Digital Logic Systems is a Computer Systems (Senior CI) topic in the RAS/RPSC syllabus. This page gathers exam-style Paper - II (viii) — Digital Logic Systems multiple-choice questions with correct answers and explanations, so aspirants can test recall and revise frequently examined concepts.
Practice 45 Paper - II (viii) — Digital Logic Systems multiple-choice questions with detailed answers and explanations. Ideal for RAS/RPSC exam preparation.
Reviewed by: Aspirant Academy Editorial Team
Q1. A full adder has inputs A, B and Cin. Which pair correctly gives its Sum and Carry output?
Explanation
A full adder adds three one-bit inputs. The Sum bit is 1 for an odd number of 1s, hence A ⊕ B ⊕ Cin. The Carry bit is 1 whenever at least two inputs are 1, represented by AB + ACin + BCin.
Q2. Which step is essential when designing a synchronous sequential system from a state diagram?
Explanation
A state diagram must be converted into hardware by encoding states, building the state table, selecting flip-flops, deriving excitation or next-state equations, and then realizing those equations with combinational logic feeding commonly clocked storage elements.
Q3. For a half-subtractor with minuend A and subtrahend B, which pair gives Difference and Borrow respectively?
Explanation
A half-subtractor compares A - B. The difference bit is 1 when the inputs differ, giving A ⊕ B. Borrow is needed only for A = 0 and B = 1, which is represented by A̅B.
Q4. In a full subtractor with inputs A, B and Bin, what is the correct expression for the Difference output?
Explanation
A full subtractor computes A minus B minus Bin for one bit. The Difference output is the modulo-2 result, so it is 1 when an odd number of A, B and Bin inputs are 1. That is represented by A XOR B XOR Bin; borrow logic is handled by a separate output.
Q5. In a full adder with inputs A, B, and Cin, which pair correctly represents Sum and Carry-out?
Explanation
A full adder adds three one-bit inputs. The Sum bit is 1 for an odd number of 1s, giving A xor B xor Cin. The Carry-out is 1 when two or three inputs are 1, so it is the majority term AB + BCin + ACin.
Unlimited practice on Paper - II (viii) — Digital Logic Systems comes with the RAS Test Series + Practice pack. Sign up to save progress; practice sets open with a pack or Gate Pass.
Q6.
Q7.
Q8.
Q9.
Q10.
Q11.
Q12.
Q13.
Q14.
Q15.
40 more questions can appear in generated practice.
Continue your Computer Systems (Senior CI) preparation with these related topics.
Unlimited practice comes with the RAS Test Series + Practice pack. Create a free account to save progress and choose a pack or Gate Pass when you are ready.
