Electronics — Part 1 MCQs with Explanations

is a common-emitter amplifier is the correct answer to “The circuit shown above”. This question is standard in competitive examination syllabi for Electronics.

1 OR gate is the correct answer to “The Boolean expression $$B\left( {A + B} \right) + A\left( {\overline B + A} \right)$$ can be realized using minimum number of”. This question is standard in competitive examination syllabi for Electronics.

the fH increases by 100 times is the correct answer to “An amplifier of gain 1000 is made into a feedback amplifier by feeding 9.9% of its output voltage in series with the input opposing. If f L = 20 Hz and f H = 200 kHz for the amplifier without feedback, then due to the feedback”. This question is standard in competitive examination syllabi for Electronics.

OR gate for a negative logic system is the correct answer to “The following circuit (where, R L ≫ R) performs the operation of”. This question is standard in competitive examination syllabi for Electronics.

Q2 = 1, Q1 = 1 is the correct answer to “In the circuit shown, the ports Q 1 and Q 2 are in the states Q 1 = 1, Q 2 = 0. The circuit is now subjected to two complete clock pulses. The state of these ports now becomes”. This question is standard in competitive examination syllabi for Electronics.

52 is the correct answer to “For the circuit shown below, the potential difference (in volt) across R L is”. This question is standard in competitive examination syllabi for Electronics.

$$\frac{{44}}{\pi }$$ is the correct answer to “An AC voltage of 220 V(rms) is applied to the primary of a 10 : 1 step-down transformer. The secondary of the transformer is centre tapped and connected to a full-wave rectifier with a load resistance. The DC voltage appearing the load is”. This question is standard in competitive examination syllabi for Electronics.

an OR gate is the correct answer to “The circuit shown in the figure below function as”. This question is standard in competitive examination syllabi for Electronics.

±5/11 V is the correct answer to “A bistable multivibrator with a saturation voltage ±5 V is shown in the diagram. The positive and negative thresholds at the inverting terminal for which the multivibrator will switch to the other state, are”. This question is standard in competitive examination syllabi for Electronics.

PQ' + Q = P is the correct answer to “Which of the given relations between the Boolean variables P and Q are not correct? (In the notation used here, P' denotes not P and Q' denotes not Q)”. This question is standard in competitive examination syllabi for Electronics.

0.1 dB is the correct answer to “The Common Mode Rejection Ratio (CMRR) of a differential amplifier using an operational amplifier is 100 dB. The output voltage for a differential input of 200 μV is 2 V. The common mode gain is”. This question is standard in competitive examination syllabi for Electronics.

moves towards the saturation region with an increase in temperature is the correct answer to “A common emitter transistor amplifier circuit is operated under a fixed bias. In this circuit, the operating point”. This question is standard in competitive examination syllabi for Electronics.

R = 53 k$$\Omega $$ and R2 = 24 k$$\Omega $$ is the correct answer to “What should be the values of the components R and R 2 such that the frequency of the Wien bridge oscillator is 300 Hz? [Given, C = 0.01 μF and R 1 = 12 k$$\Omega $$ ]”. This question is standard in competitive examination syllabi for Electronics.

computer memories is the correct answer to “RAM and ROM are”. This question is standard in competitive examination syllabi for Electronics.

40 is the correct answer to “A power amplifier gives 150 W output for an input of 1.5 W. The gain in dB is”. This question is standard in competitive examination syllabi for Electronics.

$$30{I_1} - 15{I_2} = 10$$ is the correct answer to “Let $${I_1}$$ and $${I_2}$$ represents mesh currents in the loop abcda and befcb respectively. The correct expression describing Kirchhoff's voltage loop law in one of the following loops is,”. This question is standard in competitive examination syllabi for Electronics.

43 mA is the correct answer to “In the following circuit Tr 1 and Tr 2 are identical transistors having V BE = 0.7 V. The current passing through the transister Tr 2 is”. This question is standard in competitive examination syllabi for Electronics.

F = XYZ is the correct answer to “Identify the function F generated by the logic network shown.”. This question is standard in competitive examination syllabi for Electronics.

15 $$\Omega $$ and 7.5 V is the correct answer to “Assuming an ideal voltage source, Thevenin's resistance and Thevenin's voltage respectively for the above circuit are”. This question is standard in competitive examination syllabi for Electronics.

AND gate is the correct answer to “The circuit shown below can be used as”. This question is standard in competitive examination syllabi for Electronics.

voltage controlled current source is the correct answer to “A junction field effect transistor behaves as a”. This question is standard in competitive examination syllabi for Electronics.

10 V, 5 mA is the correct answer to “In the following circuit, the voltage across and the current through the 2 k$$\Omega $$ resistance are”. This question is standard in competitive examination syllabi for Electronics.

$$\overline {\text{A}} $$D is the correct answer to “The Boolean expression Y = $$\overline {{\text{ABC}}} $$ D + $$\overline {{\text{AB}}} $$ CD + $$\overline {\text{A}} $$B$$\overline {\text{C}} $$ D + $$\overline {\text{A}} $$BCD reduces to”. This question is standard in competitive examination syllabi for Electronics.

negative and 5.2 × 1019 m-3 is the correct answer to “A doped germanium crystal of length 2 cm, breadth 1 cm and width 1 cm, carries a current of 1 mA along its length parallel to +X-axis. A magnetic field of 0.5 T is applied along +Z-axis. Hall voltage of 6 mV is measured with negative polarity at y = 0 plane. The sign and concentration of the majority charge carrier are, respectively [Given, e = 1.6 × 10 -19 C]”. This question is standard in competitive examination syllabi for Electronics.

$$Y = \overline B $$ is the correct answer to “In the given digital logic circuit, A and B form the inputs. The output Y is”. This question is standard in competitive examination syllabi for Electronics.

80 mV is the correct answer to “Figure shows a common emitter amplifier with β = 100. What is the maximum peak-to-peak input signal (V s ) for which distortion-free output may be obtained? [ Assume V BE = 0 and r e = 20 $$\Omega $$ ]”. This question is standard in competitive examination syllabi for Electronics.

$$A \cdot \overline B \cdot \overline C + \overline A \cdot D$$ is the correct answer to “The following Boolean expression $$Y = A \cdot \overline B \cdot \overline C \cdot \overline D + \overline A \cdot B \cdot \overline C \cdot D + \overline A \cdot \overline B \cdot \overline C \cdot D + \overline A \cdot \overline B \cdot \overline C \cdot D + \overline A \cdot B \cdot C \cdot D + A \cdot \overline B \cdot \overline C \cdot D$$ can be simplified to”. This question is standard in competitive examination syllabi for Electronics.

a voltage follower is the correct answer to “The inverting input terminal of an operational amplifier (op-amp) is shorted with the output terminal apart from being grounded. A voltage signal V 1 is applied to the non-inverting input terminal of the op-amp. Under this configuration, the op-amp function is as”. This question is standard in competitive examination syllabi for Electronics.

0.68 V is the correct answer to “A n-channel silicon (dielectric constant = 12) FET with a channel width a = 2 × 10 6 m is doped with 10 21 electron/m 3 . The pinch-off voltage is”. This question is standard in competitive examination syllabi for Electronics.

A and D is the correct answer to “A ripple counter designed with J-K flip-flops provided with CLEAR (Cl.) input is shown in the figure. In order that this circuit functions as a MOD-12 counter, the NAND gate inputs (X 1 and X 2 ) should be”. This question is standard in competitive examination syllabi for Electronics.

a ramp function of -4 V is the correct answer to “Figure shows a practical integrator with R s = 30 M$$\Omega $$, R F = 20 M$$\Omega $$ and C F = 0.1 μF. If a step (DC) voltage of +3 V is applied as input for 0 ≤ t ≤ 4 (t is in second), the output voltage is”. This question is standard in competitive examination syllabi for Electronics.

both biased with negative potentials is the correct answer to “Under normal operating conditions, the gate terminals of an n-channel Junction Field Effect Transistor UFET) and an n-channel Metal Oxide Semiconductor Field Effect Transistor (MOSFET) are”. This question is standard in competitive examination syllabi for Electronics.

1010 is the correct answer to “The registers Q D , Q C , Q B and Q A shown in the figure are initially in the state 1010 respectively. An input sequence SI = 0101 is applied. After two clock pulses, the state of the shift registers (in the same sequence Q D Q C Q B Q A ) is”. This question is standard in competitive examination syllabi for Electronics.

-7 V is the correct answer to “The output V o of the ideal op-amp circuit shown in the figure is”. This question is standard in competitive examination syllabi for Electronics.

full-wave rectifier with lav = 20/π mA is the correct answer to “For the rectifier circuit shown in the figure, the sinusoidal voltage (V 1 or V 2 ) at the output of the transformer has a maximum value of 10 V. The load resistance R L , is 1 k$$\Omega $$. If l av is the average current through the resistor R L , the circuit corresponds to a”. This question is standard in competitive examination syllabi for Electronics.

The p-side of the junction is negatively charged is the correct answer to “Which one of the following is true for a semiconductor p-n junction with no external bias”. This question is standard in competitive examination syllabi for Electronics.

-0.006 is the correct answer to “The feedback ratio of an amplifier, which on application of a negative feedback, changes the voltage gain from -250 to -100 is”. This question is standard in competitive examination syllabi for Electronics.

two inputs and two outputs is the correct answer to “A half-adder is a digital circuit with”. This question is standard in competitive examination syllabi for Electronics.

$$2{V_m}$$ is the correct answer to “A sinusoidal input voltage V in of frequency ω is fed to the circuit shown in the figure, where C 1 ≫ C 2 . If V m is the peak value of the input voltage, then output voltage (V out ) is”. This question is standard in competitive examination syllabi for Electronics.

R1 = 30 k$$\Omega $$; R2 = 1.7 $$\Omega $$ is the correct answer to “The low-pass active filter shown in the figure has a cut-off frequency of 2 kHz and a pass band gain of 1.5. The values of the resistors are”. This question is standard in competitive examination syllabi for Electronics.