Which of the following is a characteristic of combinational circuits?
Answer: B
Combinational circuits have outputs that depend solely on the current input values, with no memory or feedback elements involved.
Q.7Easy
In the 2024-25 examination pattern, which logic family provides the lowest power consumption?
Answer: C
CMOS (Complementary Metal-Oxide-Semiconductor) logic has the lowest power consumption, making it the preferred choice for modern digital systems and portable devices.
Q.8Easy
The setup time of a flip-flop is defined as:
Answer: B
Setup time is the minimum duration the input data must remain stable and valid before the active clock edge for reliable operation.
Q.9Easy
In a Karnaugh map, what does a larger group of adjacent 1's represent?
Answer: B
Larger groups in K-maps represent simplification with fewer variables in the resulting Boolean expression, reducing circuit complexity.
Q.10Easy
In a multiplexer, the number of select lines required to select from 16 data inputs is:
Answer: B
For 2^n data inputs, n select lines are needed. 2^4 = 16, so 4 select lines are required for a 16-to-1 multiplexer.
Q.11Easy
Which of the following is used to convert analog signals to digital for processing?
Answer: C
ADCs are specifically designed to convert continuous analog signals into discrete digital representations for digital processing systems.
Q.12Easy
A JK flip-flop with J=1, K=1 and clock pulse will:
Answer: C
When both J and K inputs are 1 in a JK flip-flop, the output toggles on the clock pulse, changing from 0 to 1 or 1 to 0.
Q.13Easy
In a 4-to-1 multiplexer, how many select lines are required?
Answer: B
For a 4-to-1 multiplexer, we need log₂(4) = 2 select lines to choose one of 4 input lines.
Q.14Easy
What is the output of an SR flip-flop when S=1 and R=1 (NOR gate implementation)?
Answer: C
When both S=1 and R=1 in NOR-based SR flip-flop, both outputs become 0, which violates the Q and Q' complementary property, making it an invalid state.
Q.15Easy
Which Boolean theorem states that A + 0 = A and A · 1 = A?
Answer: B
The Identity law in Boolean algebra states that any variable combined with identity element (0 for OR, 1 for AND) remains unchanged.
Q.16Easy
In a ripple counter with 4 flip-flops, what is the maximum count?
Answer: B
A 4-bit counter can count from 0 to 2⁴-1 = 15 (binary: 0000 to 1111), giving a maximum count of 15.
Q.17Easy
What is the primary advantage of CMOS logic over TTL logic in modern designs?
Answer: B
CMOS logic offers significantly lower power consumption (only during switching) and better noise margins compared to TTL, making it ideal for modern low-power applications.
Q.18Easy
In a multiplexer with 8 input lines, how many output lines are present?
Answer: A
A multiplexer, regardless of the number of inputs, has only one output line. The select lines determine which input is routed to that output.
Q.19Easy
De Morgan's theorem states that (A·B)' equals:
Answer: A
De Morgan's first theorem states (A·B)' = A' + B'. The complement of AND equals OR of complements.
Q.20Easy
A 4-bit binary counter requires how many flip-flops to count from 0 to 15?
Answer: B
A 4-bit counter can represent 2^4 = 16 states (0 to 15), requiring exactly 4 flip-flops.
