1 In an 8085 microprocessor, which one of the following is the correct sequence of the machine cycles for the execution of the DCR M instruction? Options A) op-code fetch B) op-code fetch, memory read, memory write C) op-code fetch memory read D) op-code fetch memory write, memory write Your Answer ( Not Answered ) Correct Answer B 2 lim x � p /4 sin 2 [ x - p 4 ] x - p 4 equals Options A) 0 B) 1 2 C) 1 D) 2 Your Answer ( Not Answered ) Correct Answer D 3 Three DC currents I 1 , I 2 and I 3 meet at a node with I 1 entering and I 2 and I 3 leaving the node. I 1 and I 2 are measured as 100mA and 99 mA with a � 1% accuracy. Then the value of I 3 and the accuracy of I 3 are Options A) 1 mA � 2% B) 199 mA � 2% C) 1 mA � 2% D) 1 mA � 199% Your Answer ( Not Answered ) Correct Answer C 4 The input-output characteristic of a Schmidt trigger has a hysteresis band of � 0.1 V. If the input voltage is 5 sin (1000 p t), the delay between the corresponding zero cross-over points of the output and input signals is Options A) 6.37 m s B) 0.02 m s C) 63.7 m s D) 2.0 m s Your Answer ( Not Answered ) Correct Answer A 5 In a spirit level, 2.5mm of movement of the bubble corresponds to a tilt angle of 25 seconds. The radius of curvature of the tube of the spirit level is Options A) 52.1 m B) 34.4 m C) 26.3 m D) 15.6 m Your Answer ( Not Answered ) Correct Answer B 6 The loop transfer function of a system is given by G(S)h(s) = 10 e -Ls s . The phase cross-over frequency is 5 rad/s. The value of the dead time L is Options A) p /20 B) p /10 C) - p /20 D) zero Your Answer ( Not Answered ) Correct Answer B 7 An 8-bit microcontroller has an external RAM is the memory map from 8000H to 9FFFH. The number of bytes this RAM can store is Options A) 8193 B) 8191 C) 8192 D) 8000 Your Answer ( Not Answered ) Correct Answer C 8 Two copper-constantan thermocouples are connected such that the two constantan wires are joined together. The two copper wires are connected to the input of a low noise chopper stabilized differential amplifier having a gain of 1000. One of the thermocouple junctions is immersed in a flask containing ice and water in equal proportion. The other thermocouple is at a temperature T. If the output of the amplifier is 2.050V, the temperature T is Options A) 205�C B) 102.5�C C) 51.25�C D) 50�C Your Answer ( Not Answered ) Correct Answer D 9 The vectored address corresponding to the software interrupt command RST7 in 8085 microprocessor is Options A) 0017H B) 0027H C) 0038H D) 0700H Your Answer ( Not Answered ) Correct Answer C 10 For a first order instrument a 5% settling time is equal to Options A) three times the time constant B) two times the time constant C) the time constant D) time required for the output signal to reaches 5% of the final value Your Answer ( Not Answered ) Correct Answer A 11 The measurements of a source voltage are 5.9V, 5.7V and 6.1V. The sample standard deviation of the readings is Options A) 0.013 B) 0.04 C) 0.115 D) 0.2 Your Answer ( Not Answered ) Correct Answer D 12 In an INTEL 8085 microprocessor the ADDRESS-DATA bus and the DATA bus are Options A) Non multiplexed B) Multiplexed C) Duplicated D) Same as CONTROL bus Your Answer ( Not Answered ) Correct Answer B 13 The number of comparators required in an 8-bit flash-type AID converter is Options A) 256 B) 255 C) (8 + 2) D) 8 Your Answer ( Not Answered ) Correct Answer B 14 An ultrasonic beam of frequency 1 MHz and intensity 0.5 W/cm 2 passes through a layer of soft tissue of thickness t with an attenuation coefficient of 1.18cm -1 . The ratio of output to input power is 1/e 2 . The thickness of the tissue is Options A) 1 cm B) 1.695 cm C) 2.408 cm D) 3.712 cm Your Answer ( Not Answered ) Correct Answer B 15 A twisted pair of wires is used for connecting the signal source with the instrumentation amplifier, as it helps reducing Options A) the effect of external interference B) the error due to bias currents in the amplifier C) the loading of the source by the amplifier D) the common mode voltage Your Answer ( Not Answered ) Correct Answer C 16 The output from a 633 nm He-Ne laser comes out from the mirror with a beam diameter of lmm and diverges to the far field. It is brought to a focus by a convex lens of focal length of 17 mm. The spot size diameter of the beam at the focal point is Options A) 20 m m B) 26 m m C) 52 m m D) 13 m m Your Answer ( Not Answered ) Correct Answer C 17 International temperature scale in the range 0-630oC is defined by means of a Options A) mercury pressure spring thermometer B) platinum-platinum. 10% rhodium thermocouple C) platinum resistance thermometer D) total radiation pyrometer. Your Answer ( Not Answered ) Correct Answer D 18 A microprocessor has an instruction XOR (r 1 , r 2 ) which performs an Exclusive OR operation of registers r 1 ,r 2 and stores the result in r 1 . After the following instructions are executed XOR (r 2 , r 1 ) XOR (r 1 ,r 2 ) XOR (r 2 ,r 1 ) Which one of the following is true? Options A) Content of register r 1 is half sum of r 1 and r 2 B) Content of register r 2 is half sum of r 1 and r 2 C) Contents of registers r 1 and r 2 remain unaltered D) Contents of registers r 1 and r 2 are swapped Your Answer ( Not Answered ) Correct Answer D 19 A second order feedback system is found to be oscillating with a high frequency. The oscillations Options A) can be reduced by increasing the proportional action B) can be reduced by increasing the integral action C) can be reduced by increasing the derivative action D) cannot be reduced Your Answer ( Not Answered ) Correct Answer B 20 For a suppressed carrier amplitude modulator (AM-SC) system, the carrier and the modulating inputs are x c (t) = cos w c t and x m (t) = 0.5 sin w m t, respectively. The output of the system is proportional to Options A) sin ( w c + w m ) t � sin ( w c - w m ) t B) sin ( w c + w m ) t + cos ( w c - w m ) t C) (1 + 0.5 sin w m t) cos w c t D) (1- 0.5 sin w m t) cos w c t Your Answer ( Not Answered ) Correct Answer B |
