MCQOPTIONS
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MCQOPTIONS
This section includes 2670 Mcqs, each offering curated multiple-choice questions to sharpen your Railways knowledge and support exam preparation. Choose a topic below to get started.
| 1751. |
The capacitance between points P and Q in circuit shown in fig is |
| A. | \[1\mu F\] |
| B. | \[1.5\mu F\] |
| C. | \[9\mu F\] |
| D. | \[6.75\mu F\] |
| Answer» B. \[1.5\mu F\] | |
| 1752. |
In pneumatic systems, electrical resistance is analogous to a |
| A. | restriction to flow |
| B. | volume of air |
| C. | filled helical tube |
| D. | none of these |
| Answer» B. volume of air | |
| 1753. |
Which one of the following statements regarding state space method is NOT TRUE? |
| A. | It gives compact and convenient form. |
| B. | It reduces complexity. |
| C. | Direct programming is possible on analog computer. |
| D. | None of these |
| Answer» C. Direct programming is possible on analog computer. | |
| 1754. |
The Laplace Transform of unit step function and ramp functions respectively are |
| A. | \[\frac{1}{{{s}^{2}}},\,\,\frac{1}{s}\] |
| B. | \[\frac{1}{s},\,\,\frac{1}{{{s}^{2}}}\] |
| C. | \[\frac{1}{s},\,\,\frac{1}{{{s}^{3}}}\] |
| D. | \[\frac{1}{{{s}^{3}}},\,\,\frac{1}{s}\] |
| Answer» C. \[\frac{1}{s},\,\,\frac{1}{{{s}^{3}}}\] | |
| 1755. |
A good control system should be sensitive to ____ |
| A. | Internal disturbances |
| B. | Environmental parameters |
| C. | Parametric variations |
| D. | Input signals (except noise) |
| Answer» E. | |
| 1756. |
Tow blocks having respective functions as \[{{G}_{1}}\] and \[{{G}_{2}}\] are connected in series cascade. Their resultant will be |
| A. | \[{{G}_{1}}\,\,{{G}_{2}}\] |
| B. | \[{{G}_{1}}+{{G}_{2}}\] |
| C. | \[{{G}_{1}}/{{G}_{2}}\] |
| D. | \[{{G}_{2}}/{{G}_{1}}\] |
| Answer» B. \[{{G}_{1}}+{{G}_{2}}\] | |
| 1757. |
Type 0 systems are unsuitable ____ |
| A. | For ramp inputs |
| B. | If input is parabolic in nature. |
| C. | Both a & b |
| D. | None of the above |
| Answer» D. None of the above | |
| 1758. |
For which systems are the signal flow graphs applicable! |
| A. | Causal |
| B. | Invertible |
| C. | linear time invariant system |
| D. | Dynamic |
| Answer» D. Dynamic | |
| 1759. |
In block diagram representation, what do the lines connecting the blocks, known as? |
| A. | Branches |
| B. | Nodes |
| C. | Datums |
| D. | Sources |
| Answer» B. Nodes | |
| 1760. |
For the elimination of feedback loops, the derivation based on transfer function of____ loop is use [d] |
| A. | Open |
| B. | Closed- |
| C. | Both a & b |
| D. | None of the above |
| Answer» C. Both a & b | |
| 1761. |
Laplace transform of an impose response is regarded as ___ function of the system |
| A. | Analytic |
| B. | Parabolic |
| C. | Transfer |
| D. | Hypothetical |
| Answer» D. Hypothetical | |
| 1762. |
State space analysis is applicable even if the initial conditions are ___ |
| A. | Zero |
| B. | Non-zero |
| C. | Equal |
| D. | Not equal |
| Answer» C. Equal | |
| 1763. |
Which among the following are solely responsible in determining the speed of response of control system? |
| A. | Poles |
| B. | Zeros |
| C. | Speed of input |
| D. | All of the above |
| Answer» B. Zeros | |
| 1764. |
Where are the dummy nodes added in the branch with unity gain? |
| A. | At input & output nodes |
| B. | Between chain nodes |
| C. | Both a & b |
| D. | None of the above |
| Answer» B. Between chain nodes | |
| 1765. |
In a parallel combination, the direction of flow of signals through blocks in parallel must resemble to the main |
| A. | Forward |
| B. | Feedback |
| C. | Opposite |
| D. | Diagonal |
| Answer» B. Feedback | |
| 1766. |
A system has the transfer function \[(1-s)\,\,(1+s)\] It is known as a |
| A. | 1 |
| B. | \[-0\] |
| C. | \[-1\] |
| D. | None of these |
| Answer» B. \[-0\] | |
| 1767. |
In a signal flow graph, nodes are represented by small |
| A. | Circles |
| B. | Squares |
| C. | Arrows |
| D. | Pointers |
| Answer» B. Squares | |
| 1768. |
The output signal is fed back at the input side from the ____point |
| A. | Summing |
| B. | Differential |
| C. | Take-off |
| D. | All of the above |
| Answer» D. All of the above | |
| 1769. |
How is an output represented in the control systems? |
| A. | \[r(t)\] |
| B. | \[c(t)\] |
| C. | \[x(t)\] |
| D. | \[y(t)\] |
| Answer» C. \[x(t)\] | |
| 1770. |
Which among the following is not an advantage of an open loop system? |
| A. | Simplicity in construction & design |
| B. | Easy maintenance |
| C. | rare problems of stability |
| D. | Requirement of system recalibration from time to time |
| Answer» E. | |
| 1771. |
The transfer function Y (s) / U (S) of a system described by the state equations \[dx/dt=-2x+2u\]and \[y\,\,(t)=0.5x\] is: |
| A. | \[0.5/(s-2)\] |
| B. | \[1/(s-2)\] |
| C. | \[0.5/(s+2)\] |
| D. | \[1/(s+2)\] |
| Answer» E. | |
| 1772. |
In a system non-linearity may be introduced due to |
| A. | backlash in gears |
| B. | end positions in detectors |
| C. | saturation effects in amplifiers |
| D. | any of the above |
| Answer» E. | |
| 1773. |
The analysis of multiple input multiple output is conveniently studied by; |
| A. | State space analysis |
| B. | Root locus approach |
| C. | Characteristic equation approach |
| D. | Nicholas chart. |
| Answer» B. Root locus approach | |
| 1774. |
A transfer function of control system does not have pole-zero cancellation. Which one of the following statement is true? |
| A. | System is neither controllable nor observable |
| B. | System is completely controllable & observable |
| C. | System is observable but uncontrollable |
| D. | System is controllable but unobservable |
| Answer» C. System is observable but uncontrollable | |
| 1775. |
In force-current analogy, displacement is analogous to |
| A. | magnetic flux linkage |
| B. | capacitance |
| C. | voltage |
| D. | inductance |
| Answer» B. capacitance | |
| 1776. |
Backlash in a stable control system can cause |
| A. | over damping |
| B. | low-level oscillations |
| C. | underdamping |
| D. | poor stability at reduced values of open-loop gain |
| Answer» C. underdamping | |
| 1777. |
Laplace Transform of the functions \[{{e}^{-1}}\]and\[{{e}^{-2t}}\] are |
| A. | \[\frac{1}{s+1},\,\,\frac{1}{s-2}\] |
| B. | \[\frac{1}{s-1},\,\,\frac{1}{s-2}\] |
| C. | \[\frac{1}{s+1},\,\,\frac{1}{s-2}\] |
| D. | None of these |
| Answer» B. \[\frac{1}{s-1},\,\,\frac{1}{s-2}\] | |
| 1778. |
In pneumatic systems, electrical capacitance is analogous to |
| A. | restriction to flow |
| B. | volume of air |
| C. | filled helical tube |
| D. | none of these |
| Answer» C. filled helical tube | |
| 1779. |
5 percent?proportional band means control output |
| A. | change by 5 percent |
| B. | change from maximum to minimum for 5 percent change in measured variable |
| C. | changes by 95 percent |
| D. | none of these |
| Answer» C. changes by 95 percent | |
| 1780. |
An AC servomotor (2 ? phase induction motor) has a rotor with |
| A. | high resistance winding |
| B. | very small di ameter to reduce inertia |
| C. | very small axial length to reduce inertia |
| D. | both [a] and [b] |
| Answer» E. | |
| 1781. |
In a hybrid feedback control system carrier signals are |
| A. | d. c. only |
| B. | a. c. only |
| C. | both d. c. and a. c. |
| D. | none of these |
| Answer» B. a. c. only | |
| 1782. |
The sensitivity of a closed loop control system to variations in gain and load disturbance depends upon |
| A. | loop gain |
| B. | frequency |
| C. | forward gain |
| D. | all of these |
| Answer» E. | |
| 1783. |
Proportional band of a controller is defined as the range of |
| A. | measured variables from set value |
| B. | measured variables through which the air output changes from maximum to minimum |
| C. | air output as measured variable varies from maximum to minimum |
| D. | none of these |
| Answer» C. air output as measured variable varies from maximum to minimum | |
| 1784. |
For the minimum phase system to be stable |
| A. | phase margin should be negative and gain margin positive |
| B. | phase margin should be positive and gain margin negative |
| C. | both gain margin and phase margin should be positive |
| D. | both gain margin and phase margin should be negative |
| Answer» D. both gain margin and phase margin should be negative | |
| 1785. |
Given that D=rotor diameter and L=axial length, a hid performance ac servo-motor is characterized by |
| A. | large D, large L |
| B. | large D, small L |
| C. | small D, large L |
| D. | small D, large L |
| Answer» E. | |
| 1786. |
A system has the transfer function\[(1-s)/(1+s)\]. What is its gain at 1 rad/sec? |
| A. | low?pass system |
| B. | high?pass system |
| C. | all?pass system |
| D. | none of these |
| Answer» C. all?pass system | |
| 1787. |
Damping due to back emf is observed in |
| A. | armature controlled d. c. motor |
| B. | field controlled d. c. motor |
| C. | a. c. servomotor |
| D. | none of these |
| Answer» B. field controlled d. c. motor | |
| 1788. |
The function \[u\,\,(t-{{t}^{0}})=\left[ \begin{matrix} 1 & t>{{t}_{0}} \\ 0 & t |
| A. | unit step function |
| B. | unit ramp function |
| C. | unit impulse function |
| D. | none of these |
| Answer» B. unit ramp function | |
| 1789. |
The transfer function of a system is used to determine |
| A. | the output for a given input |
| B. | the type of system |
| C. | the input for given output |
| D. | the steady state gain |
| Answer» B. the type of system | |
| 1790. |
Human system can be considered as a |
| A. | open-loop system |
| B. | closed-loop system with single feedback |
| C. | closed-loop system with single feedback |
| D. | none of these |
| Answer» D. none of these | |
| 1791. |
____ has some roots with real parts equal to zero but none with positive real parts. |
| A. | Marginally stable |
| B. | 'Absolutely stable |
| C. | Absolutely unstable |
| D. | Stable |
| Answer» B. 'Absolutely stable | |
| 1792. |
Vacuum diode is a two-electrode vacuum tube, first is called cathode and the second is called |
| A. | symbol |
| B. | rectifier |
| C. | anode |
| D. | none of these |
| Answer» D. none of these | |
| 1793. |
When PN junction is in forward bias, by increasing the battery voltage |
| A. | current through PN junction increases |
| B. | circuit resistance increases |
| C. | both [a] and [b] |
| D. | none of these |
| Answer» B. circuit resistance increases | |
| 1794. |
Consider the following statements: 1. Grinding 2. Coating 3. Hammer peening For improving the fatigue strength of steel. Of the above statements: |
| A. | 1 and 2 are correct |
| B. | 2 and 3 are correct |
| C. | 1 and 3 are correct |
| D. | 1, 2 and 3 are correct. |
| Answer» D. 1, 2 and 3 are correct. | |
| 1795. |
Which antenna does not depend on frequency? |
| A. | Log periodic antenna |
| B. | Yagi antenna |
| C. | Both [a] and [b] |
| D. | None of the above |
| Answer» B. Yagi antenna | |
| 1796. |
How many input and output required for multiplexer? |
| A. | Many input and one output |
| B. | One input and many output |
| C. | One input and one output |
| D. | None of the above |
| Answer» B. One input and many output | |
| 1797. |
Which of the following is not a magnetic memory? |
| A. | Flip-flop |
| B. | Tape |
| C. | Drum |
| D. | Disk |
| Answer» B. Tape | |
| 1798. |
Programmable Logic Array (PLA) uses |
| A. | ROM matrices |
| B. | FROM matrices |
| C. | RAM matrices |
| D. | Silo memory |
| Answer» D. Silo memory | |
| 1799. |
How many bits are required to store one BCD digit? |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» E. | |
| 1800. |
Positive integers must be represented by |
| A. | Signed numbers |
| B. | Unsigned number |
| C. | Both A and B |
| D. | None of these. |
| Answer» C. Both A and B | |