Objective Questions on Electronics | MCQ on Electronics 14

  1. When a signal of 10 mV at 75 Mhz is to be measured then which of the following instrument can be used ?

    CRO can measure low voltage high frequency signals.

  2. In phase controlled rectifiers which of the following does occur?

    In a phase controlled rectifiers, if the delay angle increases, then the angle (Φ) between the voltage and current also increases. Hence, the power factor (CosΦ) is going down.

  3. A DMA transfer implies what of the following?

    DMA stands for direct memory access. This is used for transferring the data between CPU and the input/output devices with high speed data transfer.

  4. Among the three configurations of transistors, the highest output impedance is obtained by

    In a common base configuration, the transistor will have a low input impedance, high output impedance, unity (or less) current gain and high voltage gain.

  5. The bridge used for measuring insulation of cables

    The insulation of cable is measured interms of capacitance. If the capacitance value is good, then the insulation is also good. Basically, the unknown capacitance is measured by using the Schering Bridge.

  6. CRT stands for

    CRT stands for Cathode Ray Tube. It is basically used in the Cathode Ray Oscilloscopes.

  7. In microprocessor, "SP" used in stack is actually

    SP stands for stack pointer. The SP can be used to temporarily store the 16-bit memory address as well as data.

  8. A single - phase induction regulator is a constant input transformer to obtain smooth variation of the output voltage by varying

    An electron moving in a uniform magnetic field that experiences the magnetic force when the angle between the direction of the electron's motion and the direction of the magnetic field changes. Based on that generation of magnetic force, the EMF is generated in that coil. So, if we change the angle between the magnetic forces of the primary and secondary windings, we can be obtained the smooth voltage variation in the output side.

  9. In microprocessor, stack operation is basically by

    Basically, the Stack operation is used to insert or delete the data in a particular address. For inserting the data, the PUSH instruction is used and for deleting the data, the POP instruction is used.

  10. Which bus is used for input and output in case of microprocessor operation?

    The input and output are used to control the function of a microprocessor. Hence, the control bus is used to transfer the input and output signal from microprocessor to external peripherals and or from external peripherals to microprocessor. For example, the control bus carries timing signals, read-write signals, interrupt requests and similar signals between the microprocessor and external devices.

  11. In microprocessor, input and output of data in stack is ordered by

    The working principle of stack is to add the entity to the collection, known as push and removal of an entity, known as pop. The relation between the push and pop operations is such that the stack is a Last-In-First-Out (LIFO) data structure.

  12. In microprocessor operation, which bus carry the memory addresses?

    The address bus carries binary coded numbers which identify the storage locations in the main memory that is nothing but the main memory stores the memory addresses, much like the postal code of a letter.

  13. The 2’s complement of the number of 1010101 is

    The 2’s complement of a number is nothing but the addition of 1’s complement of that number and 1. Hence, the 1’s complement of the given number is 0101010 and the 2’s complement of the number is 0101010 + 1 = 0101011.

  14. The output of the logic circuit is given below is

    Under construction.

  15. Which of the following is true for bipolar transistor ?

    Emitter is heavily doped because it should provide the charge carriers to Base and Collector region, and the Base and Collectors are lightly doped because it should accept those charge carriers.

  16. Merz price protection system is used for

    The Merz price protection system is a most common system used for the protection of internal winding faults of alternator and transformer due to the short circuit by using differential circulating current principle.

  17. The voltage across a 70 mH coil ,when the current through it is changing at the rate of 20 A / sec is

    V = L × di / dt = 70 × 10-3 × 20 = 1.4 V.

  18. Which is / are the essential features possessed by an indicating instruments?

    In an instrument, the deflecting device is used to generate the deflecting torque to the pointer or indicator. The controlling device is used to control the speed of the pointer and the damping device is used to avoid the continuous oscillations in the pointer. Hence, all the three devices are important in an indicating instrument.

  19. If in a mercury arc rectifier connections of anode and cathodes are interchanged then what will happen?

    The mercury arc rectifier consisted of a glass tube with three or more electrodes. When a given amount of current would heat up and vaporize the mercury in the tube, the full power level could travel through the vapor to the other side. The effect on the AC power waveform is that it would chop off the beginning and end of the wave, and prevent current from traveling back through, effectively acting similar to a diode. So, if we interchange the anode and cathode terminals, the mercury does not vaporize and hence the rectifier will not work.

  20. In digital electronics a full adder has how many inputs and outputs?

    In full adder there will be three inputs and two outputs – sum & carry.