Electronics And Instrumentation — Part 1 MCQs with Explanations

Piezo-electric transducers operate based on the piezoelectric effect, which is the ability of certain materials to generate an electric charge when subjected to mechanical stress . When a mechanical force is applied to a piezoelectric material, it produces a proportional voltage across its surfaces. This property is widely used in sensors, actuators, and measurement instruments . Option B (Vibrations) is incorrect because while vibrations may cause mechanical stress, it is the force behind the vibration that activates the piezoelectric effect. Option C (Illuminations) and Option D (Heat) are unrelated to the working principle of piezoelectric transducers. Therefore, the correct answer is Option A.

Statement 1 (S1) is true because a transducer is a device that converts a physical quantity (such as temperature, pressure, or light) into an electrical quantity (such as voltage or current). This conversion is essential for measurement and control systems in electronics and instrumentation. Statement 2 (S2) is also true because a transducer is commonly referred to as a sensor . Sensors detect changes in physical conditions and convert them into signals that can be measured and analyzed. Therefore, both statements accurately describe the nature and function of transducers.

Diffraction is the correct answer to “The shorter wave length of the electron permits the detailed examination of tiny objects due to reduction of __________ effects”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Both S1 & S2 are true is the correct answer to “Pick the correct statement regarding functions of a transducer S1: Sense the magnitude, change in & / or frequency of same measurand S2: To provide electrical output that furnishes accurate, quantitative data about the measurand”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Both S1 and S2 are true is the correct answer to “S1: In multimode fiber optics, intensity modulating schemes can be employed. S2: Schemes using polarizing techniques need birefringent fiber.”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Differential mode gain to common mode gain is the correct answer to “Common mode rejection ratio is defined as ratio of”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Encoder is the correct answer to “Which of the following is a digital transducer”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Power amplifier is the correct answer to “___________ amplifier is used to drive the recorder.”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Passive transducer is the correct answer to “The transducers which requires an external power and their output is a measure of some variation such as resistance, inductance, capacitance etc., are called as”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

200 kΩ is the correct answer to “What is the total resistance of a voltmeter on the 10 V range when the meter movement is rated for 50 µA of full-scale current”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Galvanometric is the correct answer to “Which of the following recorder gives slow response”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Noise factor of unity is the correct answer to “An ideal amplifier has”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

20 kΩ/V is the correct answer to “If the full-scale deflection current of a multimeter is 50 µA, its sensitivity is”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Voltmeter of range 10 V is the correct answer to “Which of the following is likely to have the largest resistance”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Current is the correct answer to “A VTVM is never used to measure ___________.”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

All of above is the correct answer to “A CRO is used to measure ___________.”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

2.5 micron to 6 micron is the correct answer to “In foil strain gauge the thickness of foil varies from”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Is decreased is the correct answer to “If the negative potential on the control grid of CRT is increased, the intensity of spot ___________.”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Attenuation is the correct answer to “Isolation amplifier actually operates on the principle of”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Secondary emission is the correct answer to “Storage oscilloscope operates on the principle of”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Mutual inductance is the correct answer to “The principle of operation of LVDT is based on the variation of”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

LDR is the correct answer to “_____________ is the example of photo emissive cell”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Parabolic path is the correct answer to “In a graded index fiber, the total reflected light takes a ___________.”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

80 dB is the correct answer to “The CMRR of a typical IC OPAMP is”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

S1 is true & S2 is false is the correct answer to “In PMMC writing system, the magnitude of pen deflection is proportional to S1: Current flowing through the coil S2: Voltage in the coil”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Sawtooth wave is the correct answer to “The horizontal plates of a CRO are supplied with ___________ to observe the waveform of signal.”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Ability to amplify Dc and low frequency signals is the correct answer to “The outstanding characteristics of a D.C. amplifier is its”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Dynamic is the correct answer to “Capacitive transducers are normally employed for___________ measurements.”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Active is the correct answer to “Self generating type transducers are ___________ transducers.”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Digital is the correct answer to “The transducers that converts the input signal into the output signal, which is a discrete function of time is known as ___________ transducer.”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Very low is the correct answer to “An ammeter should have ___________ resistance.”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Very high is the correct answer to “A voltmeter should have ___________ resistance.”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Zero is the correct answer to “An ideal ammeter has ___________ resistance.”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Eddy current is the correct answer to “LVDT is an/a ___________ transducer.”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Converts DC signal from low frequency to high frequency is the correct answer to “A chopper amplifier”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

1.5 to 2.0 is the correct answer to “The sensitivity factor of strain gauge is normally of the order of”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

S2 is true & S1 is false is the correct answer to “The change in resistance of a metal wire owing to strain is due to S1: Change in dimension of wire expressed by factor (1-2µ) S2: Change in resistance”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Presence of external and internal capacitance is the correct answer to “The amplifier gain varies with frequency. This happens mainly due to”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Reduces voltage gain is the correct answer to “The negative feed back in an amplifier”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.

Changes the shape of the waveform of the signal is the correct answer to “The improper response time of the amplifier in the biomedical recorders”. This question is standard in competitive examination syllabi for Electronics And Instrumentation.