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.62Easy
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.63Easy
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.64Easy
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.65Easy
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.
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Q.66Easy
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.67Easy
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.68Easy
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.
Q.69Easy
In a common emitter amplifier, the voltage gain is maximum when the load resistance is
Answer: C
Voltage gain AV = gm × RL. Maximum gain occurs when load resistance is much larger than the output impedance of the transistor, limited only by practical considerations.
Q.70Easy
The input impedance of a common base amplifier is
Answer: B
Common base configuration has very low input impedance (typically 20-100 Ω) because the input is at the emitter which is forward biased.
Q.71Easy
For maximum power transfer in an amplifier circuit, the load impedance should be
Answer: B
Maximum power transfer theorem states that maximum power is delivered when load impedance is the complex conjugate of source impedance (ZL = ZS*).
Q.72Easy
Which configuration provides the highest voltage gain among the three BJT amplifier configurations?
Answer: C
Common emitter provides both voltage and current gain with gain values typically 100-1000. CB provides only current gain, CC provides only voltage gain close to 1.
Q.73Easy
An ideal operational amplifier has the following characteristics EXCEPT
Answer: B
Ideal op-amp has: infinite input impedance (Zin→∞), infinite open-loop gain (A→∞), zero output impedance (Zout→0), infinite bandwidth (BW→∞).
Q.74Easy
In a non-inverting amplifier configuration with feedback resistors RF and Ri, the voltage gain is
Answer: A
Non-inverting amplifier gain Av = 1 + (RF/Ri). With RF=0 (short circuit), gain=1 (unity gain buffer). As RF increases, gain increases.
Q.75Easy
An inverting amplifier using op-amp has Rf = 100 kΩ and Rin = 10 kΩ. What is the voltage gain magnitude?
Answer: A
For inverting amplifier, Gain = -Rf/Rin = -100k/10k = -10. The negative sign indicates 180° phase shift.
Q.76Easy
In a Hartley oscillator, the frequency of oscillation is determined by which circuit element combination?
Answer: B
Hartley oscillator uses two inductors and one capacitor in the tank circuit. Frequency f = 1/(2π√L_eq×C) where L_eq is equivalent inductance.
Q.77Easy
Which type of feedback is applied in a non-inverting amplifier configuration?
Answer: B
Non-inverting amplifier uses negative feedback from output to inverting input, which reduces gain but improves linearity, bandwidth, and input impedance.
Q.78Easy
For an ideal op-amp, the input offset voltage is:
Answer: B
An ideal op-amp has zero input offset voltage, zero input bias current, infinite gain, infinite input impedance, and zero output impedance.
Q.79Easy
A transistor amplifier has input signal of 10 mV and output signal of 5 V. What is the voltage gain in dB?
Answer: A
Gain = Vout/Vin = 5V/10mV = 500. Gain (dB) = 20 log₁₀(500) ≈ 54 dB.
Q.80Easy
A power amplifier delivers 100 W to a 8 Ω load. What is the RMS output voltage? (Assuming pure resistive load)
Answer: A
P = V²/R → V = √(P×R) = √(100×8) = √800 ≈ 28.3 V RMS.
