In a multiplexer (MUX) with 3 select lines, how many input lines can it handle?
Answer: C
A multiplexer with n select lines can handle 2^n input lines. For 3 select lines: 2^3 = 8 input lines.
Q.22Easy
A demultiplexer (DEMUX) with 4 select lines has how many output lines?
Answer: C
A demultiplexer with n select lines has 2^n output lines. For 4 select lines: 2^4 = 16 output lines.
Q.23Easy
Which type of flip-flop has the simplest truth table and is used for frequency division?
Answer: B
A T flip-flop toggles its output when T=1 and holds when T=0, making it ideal for frequency division and counter design.
Q.24Easy
Which of the following is a volatile memory?
Answer: C
RAM (Random Access Memory) is volatile and loses all data when power is removed. ROM, EPROM, and Flash memory are non-volatile.
Q.25Easy
Which of the following is a sequential circuit?
Answer: C
Sequential circuits have memory elements (flip-flops) and their output depends on past inputs. Flip-flops are the basic sequential elements; multiplexers, encoders, and decoders are combinational circuits.
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Q.26Easy
In state machine design, if a machine has 15 different states, the minimum number of flip-flops needed is?
Answer: B
To represent 15 states, we need n flip-flops such that 2^n ≥ 15. Since 2^4 = 16 ≥ 15, minimum 4 flip-flops are required.
Q.27Easy
In a 3-to-8 decoder, if the binary input is 101, which output line will be activated?
Answer: A
Binary 101 = 5 in decimal, so output line 5 is activated in a decoder.
Q.28Easy
Which of the following logic gates has an output of 1 only when both inputs are different?
Answer: A
XOR (Exclusive OR) produces 1 when inputs are different and 0 when they are same.
Q.29Easy
What is the Boolean expression for a 2-input NAND gate?
Answer: B
NAND gate is the complement of AND, so Y = (A.B)' where . represents AND operation.
Q.30Easy
In a Multiplexer (MUX), how many select lines are required for an 8:1 MUX?
Answer: B
For 2^n inputs, n select lines are needed. For 8 inputs, log₂(8) = 3 select lines.
Q.31Easy
What is the primary purpose of using parity bits in error detection?
Answer: B
Parity bits are used for error detection by tracking whether the number of 1s in data is even or odd.
Q.32Easy
Which semiconductor memory loses its data when power is switched off?
Answer: C
DRAM (Dynamic RAM) is volatile and requires periodic refreshing. Data is lost without power, unlike non-volatile memories like ROM, EEPROM, and Flash.
Q.33Easy
What is the truth table output for a D flip-flop when CLK = 1 and D = 1?
Answer: B
In a D flip-flop, Q takes the value of D on the clock edge. When D = 1, Q becomes 1 and Q' becomes 0.
Q.34Easy
What is the output of a full adder when A=1, B=1, and Cin=1?
Answer: C
Full adder: A+B+Cin = 1+1+1 = 3 (binary 11). Sum = 1, Carry out = 1.
Q.35Easy
In a 8×4 RAM configuration, what do 8 and 4 respectively represent?
Answer: B
In RAM notation m×n, m represents number of addressable locations and n represents bits per location.
Q.36Easy
In a JK flip-flop, what happens when both J and K inputs are 1?
Answer: B
When J=1 and K=1, the JK flip-flop enters toggle mode, changing its state with each clock pulse.
Q.37Easy
A multiplexer with 16 inputs requires how many select lines?
Answer: C
For 2^n inputs, n select lines are needed. For 16 = 2^4 inputs, 4 select lines are required.
Q.38Easy
In a 3-bit binary counter, how many clock pulses are needed to complete one full cycle?
Answer: C
A 3-bit counter can count from 000 to 111 (0 to 7 in decimal), requiring 2^3 = 8 clock pulses to complete one full cycle.
Q.39Easy
Which of the following is a non-volatile memory type commonly used in embedded systems?
Answer: C
Flash memory is non-volatile (retains data without power), widely used in embedded systems, SSDs, and microcontrollers as program storage.
