Electronics Engineering Multiple Choice Questions and Answers (MCQs) Part 9:
343. When an 8086 executes an INT type instruction, it
(a) resets both IF and TF flags.
(b) resets all flags.
(c) sets both IF and TF.
(d) resets the CF and TF.
Answer : (c) sets both IF and TF.
344. In an 8085 microprocessor, which one of the following instructions changes the content of the accumulator?
(a) MOV B, M
(b) PCHL
(c) RNZ
(d) SBI BEH
Answer : (d) SBI BEH
345. A microprocessor based system can perform many different functions, because
(a) its operation is controlled by software.
(b) it is digital system.
(c) it uses a RAM.
(d) it can be controlled by input and output devices.
Answer : (a) its operation is controlled by software.
346. Which one of the following register of 8085 microprocessor is not a part of programming model ?
(a) Instruction register.
(b) Memory address register.
(c) Status register.
(d) Temporary data register.
Answer : (c) Status register.
347. The first machine cycle of an instruction is always
(a) a memory read cycle.
(b) a fetch cycle.
(c) an I/O read cycle.
(d) a memory write cycle.
Answer : (b) a fetch cycle.
348. In a microprocessor, the address of the next instruction to be executed, is stored in
(a) stack pointer.
(b) address latch.
(c) program counter.
(d) general purpose register.
Answer : (c) program counter.
349. Which one of the following statements does not describe property/characteristic of a stack pointer-register in 8085 microprocessor?
(a) It points to top of the stack.
(b) It is UP/DOWN counter.
(c) It is automatically initialized to 0000H on power-on.
(d) It is a 16-bit register.
Answer : (c) It is automatically initialized to 0000H on power-on.
350. Which one of the following register of 8085 microprocessor is not a part of programming model?
(a) Instruction register.
(b) Memory address register.
(c) Status register.
(d) Temporary data register.
Answer : (c) Status register.
351. If the accumulator of an Intel 8085A microprocessor contains 37H and the previous operation has set the carry flag, the instruction ACI56H will result in
(a) 8E H
(b) 94 H
(c) 7E H
(d) 84 H
Answer : (a) 8E H
352. The contents of Program Counter (PC), when the microprocessor is reading from 2FFF H memory location, will be
(a) 2FFE H
(b) 2FFF H
(c) 3000 H
(d) 3001 H
Answer : (c) 3000 H
353. In 8085 microprocessor, how many interrupts are maskable.
(a) Two.
(b) Three.
(c) Four.
(d) Five.
Answer : (c) Four.
354. In an Intel 8085A, what is the content of the Instruction Register (IR)?
(a) Op-code for the instruction being executed.
(b) Operand for the instruction being executed.
(c) Op-code for the instruction to be executed next.
(d) Operand for the instruction to be executed next.
Answer : (a) Op-code for the instruction being executed.
355. An output device is interfaced with an 8085 microprocessor as memory-mapped I/O. The address of the device is 1000 H. In order to output data from the accumulator to the device, what will be the sequence of instructions?
(a) LXI H, 1000H MOV A, M
(b) LXI H, 1000H MOV M, A
(c) LHLD 1000H MOV A, M
(d) LHLD 1000H MOV M, A
Answer : (b) LXI H, 1000H MOV M, A
356. Which one of the following is used as the interface chip for data transmission between 8086 and a 16-bit ADC ?
(a) 8259
(b) 8255
(c) 8253
(d) 8251
Answer : (b) 8255
357. If 8255A chip is selected when A2 to A7 pins are 1, what is the address of Port C ?
(a) F C
(b) F D
(c) F B
(d) F E
Answer : (b) F D
358. In 8086, if the content of the code segment register is 1FAB and the content of the IP register is 10A1, than the effective memory address is
(a) IFBCO.
(b) 304C.
(c) FDB5.
(d) 20B51.
Answer : (d) 20B51.
359. An Assembler for a microprocessor is used for
(a) assembly of processors in a production line.
(b) creation of new programmes using different modules.
(c) translation of a program from assembly language to machine language.
(d) translation of a higher level language into English text.
Answer : (c) translation of a program from assembly language to machine language.
360. Which one of the following operators of high level language is used to eliminate the run-time cost of redundant address calculations?
(a) Arithmetic.
(b) Assignment.
(c) Logical.
(d) Relational.
Answer : (b) Assignment.
361. The usage of electronic instruments is becoming more extensive because they have
(a) a high sensitivity and reliability.
(b) a fast response and compatability with digital computers.
(c) the capability to respond to signals from remote places.
(d) All of the above.
Answer : (d) All of the above.
362. What is an advantage of an electronic voltmeter over a nonelectronic voltmeter?
(a) Low power consumption.
(b) Low input impedance.
(c) The ability to measure wide ranges of voltages and resistances.
(d) Large portability.
Answer : (a) Low power consumption.
363. Which of the following devices is used at the first stage of an electronic voltmeter?
(a) BJT.
(b) SCR.
(c) MOSFET.
(d) UJT.
Answer : (c) MOSFET.
364. The essential elements of an electronic instrument is a/an
(a) transducer.
(b) signal conditioner.
(c) indicating device.
(d) all of the above.
Answer : (c) indicating device.
365. Electronic voltmeter provides more accurate readings in high resistance circuits as compared to non-electronic voltmeter because of its
(a) high V/ohm ratings.
(b) high ohm/V ratings.
(c) low meter resistance.
(d) high resolution.
Answer : (b) high ohm/V ratings.
366. A multimeter is used for the measurement of the following :
1. Both ac and dc voltage.
2. Both ac and dc current.
3. Resistance.
4. Frequency.
5. Power.
Select the correct answer using the codes given
(a) 1, 2 and 4.
(b) 1, 2, and 5.
(c) 1, 3 and 5.
(d) 1, 2 and 3.
Answer : (d) 1, 2 and 3.
367. Consider the following statements:
1. The main drawback of digital system is that the real world is mainly analog.
2. The major advantage of digital instruments over analog instruments is higher accuracy and better resolution.
3. Digital instruments are ordinarily used for the measurement of both analog and digital quantities.
Which of the above statements is/are correct?
(a) 1, 2 and 3.
(b) 1 and 3 only.
(c) 2 only.
(d) 1 and 2 only.
Answer : (a) 1, 2 and 3.
368. A DVM measures
(a) peak value.
(b) rms value.
(c) peak-to-peak value.
(d) average value.
Answer : (d) average value.
369. Integrating principle in the digital measurement is the conversion of
(a) voltage to time.
(b) voltage to frequency.
(c) voltage to current.
(d) current to voltage.
Answer : (b) voltage to frequency.
370. A digital voltmeter has 4 1/2 digit display.
The 1 V range can read up to
(a) 1.0000 V.
(b) 1.1111 V.
(c) 0.9999 V.
(d) 1.9999 V.
Answer : (a) 1.0000 V.
371. Beam of electrons in a cathode ray tube eminates because of
(a) secondary emission.
(b) thermionic emission.
(c) diffusion.
(d) post acceleration.
Answer : (b) thermionic emission.
372. In CRT aquadag carries
(a) aqueous solution of graphite.
(b) sweep voltage.
(c) secondary emission electrons.
(d) none of the above.
Answer : (a) aqueous solution of graphite.
373. The purpose of providing acquadag in CRT is to
(a) increase fluorescence.
(b) increase phosphorescence.
(c) protect burning of screen.
(d) remove electrostatic charge accumulation.
Answer : (d) remove electrostatic charge accumulation.
374. In a CRT the highest positive potential is given to
(a) focusing electrodes.
(b) cathode.
(c) vertical deflection plates.
(d) post deflection acceleration anode.
Answer : (d) post deflection acceleration anode.
375. It is desired to make accurate measurement of voltage using a CRO. Which of the following items should be taken into consideration in this measurement ?
1. Electrostatic deflection type CRT.
2. Magnetic deflection type CRT.
3. Small deflection for measurement at the center of the screen.
4. Large deflection to cover the entire screen.
Select the correct answer using the code given below :
(a) 1 and 4.
(b) 2 and 3.
(c) 2 and 4.
(d) 1 and 3.
Answer : (a) 1 and 4.
376. A 1000 Hz sinusoidal voltage is connected to both X and Y inputs of a CRO. Which of the following waveforms is seen on CRO?
(a) Sine wave.
(b) Circle.
(c) Ellipse.
(d) Straight line.
Answer : (d) Straight line.
377. Which of the following measurements can be made using Lissajous figures ?
1. Frequency
2. Phase difference
3. Time interval between pulses.
4. Pulse width.
5. Fundamental and higher harmonic components.
Select the correct answer using the codes given below :
(a) 1 and 2
(b) 2 and 3
(c) 3 and 4
(d) 4 and 5
Answer : (a) 1 and 2
378. The Lissajous pattern on a CRO screen is shown in the given figure:
The frequency ratio of the vertical signal to the horizontal one is
(a) 3 : 2
(b) 5 : 1
(c) 1 : 5
(d) 2 : 3
Answer : (b) 5 : 1
379. In a dual beam oscilloscope
(a) there are two separate vertical inputs and two separate horizontal inputs.
(b) there are two separate vertical inputs and there is only one set of horizontal deflection plates.
(c) there is only one vertical input but there are two separate horizontal deflection plates.
(d) there is only one vertical and one horizontal input.
Answer : (b) there are two separate vertical inputs and there is only one set of horizontal deflection plates.
380. A dual trace oscilloscope usually offers two modes, chop and alternate. The alternate mode can be used for displaying
(a) any two waveforms.
(b) two waveforms of relatively high frequency.
(c) two waveforms of relatively low frequency.
(d) one low frequency and one high frequency waveform.
Answer : (b) two waveforms of relatively high frequency.
381. Which one of the following is a passive transducer ?
(a) Piezoelectric.
(b) Thermocouple.
(c) Photovoltaic cell.
(d) LVDT.
Answer : (d) LVDT.
382. Which one of the following transducers is an active transducer ?
(a) Piezoclectnc pressure transducer.
(b) Metallic strain gauge.
(c) Semiconductor strain gauge.
(d) Platinum resistance thermometer.
Answer : (a) Piezoclectnc pressure transducer.
383. Which of the following is not an advantage of semiconductor gauges as compared to conventional strain gauges.
(a) Excellent hysteresis characteristics.
(b) Least sensitive to temperature changes.
(c) High fatigue life.
(d) Smaller size.
Answer : (b) Least sensitive to temperature changes.
384. In an LVDT, there are two secondary coils which are connected for a single output. Which one of the following is correct ?
(a) The coils are in series and in phase opposition.
(b) The coils are in parallel and in phase opposition.
(c) The coils are in series and in the same phase condition.
(d) The coils are in parallel and in the same phase condition.
Answer : (a) The coils are in series and in phase opposition.
385. Sensitivity of LVDT is mainly due to
(a) magnetic shielding of the core.
(b) permeability of the core.
(c) exact cancellation of secondary voltages.
(d) insulation used in the winding.
Answer : (c) exact cancellation of secondary voltages.
386. Which one of the following materials is not used as a piezoelectric transducer ?
(a) Rochelle salt.
(b) Lithium sulphate.
(c) Barium titanate.
(d) Tungsten oxide.
Answer : (d) Tungsten oxide.
387. Piezoelectric materials owe their property to the
(a) presence of a centre of symmetry.
(b) lack of a centre of symmetry.
(c) presence of axis of symmetry.
(d) lack of axis of symmetry.
Answer : (b) lack of a centre of symmetry.
388. The piezoelectric crystal voltage sensitivity is defined as
(a) Field developed per unit force.
(b) Field developed per unit stress.
(c) Voltage developed per unit stress.
(d) Voltage developed per unit force.
Answer : (b) Field developed per unit stress.
389. Piezoelectric transducers have the following advantage(s).
(a) These are small in size, light in weight and very rugged in construction.
(b) wide operating temperature range.
(c) very good frequency response and quite large output.
(d) all of the above.
Answer : (d) all of the above.
390. A Hall effect transducer is generally used for the measurement of
(a) power.
(b) current.
(c) displacement.
(d) voltage.
Answer : (b) current.
391. The measurement of Hall coefficient of a semiconductor with one type of charge carrier gives the information about
(a) sign of charge carrier.
(b) density of charge carrier.
(c) both sign and density of charge carrier.
(d) mass of the charge carrier.
Answer : (c) both sign and density of charge carrier.