← MES Jr. Grade
Past Questions
The rating of a 3–phase power system is given as
A)
rms phase voltage
B)
peak phase voltage
C)
rms line to line voltage
D)
peak line to line voltage
In a 3-phase power system, the system voltage rating is conventionally specified by the RMS line-to-line voltage, not phase voltage or peak voltage. For example, a 415 V 3-phase system means 415 V between any two lines. The other options are incorrect because power-system ratings are not given in peak values, and phase voltage is not the standard system rating.
The open circuit test on a transformer is mainly carried out to determine
A)
copper loss
B)
core loss
C)
total loss
D)
insulation resistance
In the open-circuit test, the transformer is energized at rated voltage with the secondary left open. The no-load current is small, so copper loss is negligible. Therefore, the input power measured mainly represents the iron/core loss (hysteresis loss + eddy current loss). Hence the test is mainly carried out to determine core loss. Copper loss is found from the short-circuit test, not the open-circuit test.
As compared to a closed-loop system, an open-loop system is
A)
more stable as well as more accurate
B)
less stable as well as less accurate
C)
more stable but less accurate
D)
less stable but more accurate
In an open-loop control system, there is no feedback path to compare the output with the desired input. Because of this, the system cannot automatically correct errors or disturbances. Hence, compared to a closed-loop system, an open-loop system is generally less accurate and also less stable. Closed-loop systems use feedback, which improves both accuracy and stability.
Which of the following plants has the minimum running cost?
A)
nuclear
B)
thermal
C)
hydro
D)
diesel
Among the given options, hydroelectric plants have the minimum running cost because water is a free fuel and the operating expenses are low once the plant is built. Nuclear, thermal, and diesel plants require costly fuel and generally have higher operating costs. Therefore, the correct answer is hydro.
If the armature current is increased to double its previous value, and the time of commutation is halved, how will the reactance voltage vary?
A)
It will be halved
B)
It will remain the same
C)
It will be doubled
D)
It will become four times
Reactance voltage during commutation is proportional to the rate of change of current, approximately V_r ∝ I/t. If the armature current is doubled and the time of commutation is halved, then the reactance voltage changes by a factor of 2 ÷ (1/2) = 4. However, in the standard commutation relation, the reactance voltage is proportional to I divided by commutation time, so doubling current and halving time gives four times the original value. Among the given options, this corresponds to option (d), not (c).
A negative sequence relay is commonly used to protect
A)
An alternator
B)
A transformer
C)
A transmission line
D)
A bus bar
A negative sequence relay protects an alternator (generator) because unbalanced loads or faults produce negative-sequence currents that create double-frequency currents in the rotor, causing overheating and damage. Hence it is commonly used for alternator protection. It is not primarily used for transformers, transmission lines, or bus bars.
Which motor can conveniently operate at lagging as well as leading power factor?
A)
squirrel-cage induction motor
B)
wound-rotor induction motor
C)
synchronous motor
D)
d.c. shunt motor
A synchronous motor can operate at different power factors by varying its field excitation. Underexcited operation makes it draw lagging current, while overexcited operation makes it draw leading current. Hence it can conveniently operate at both lagging and leading power factor. The other motors listed are generally not used for adjustable power-factor operation: induction motors usually operate at lagging power factor, and a d.c. shunt motor is not an a.c. power-factor machine.
DML is provided for
A)
Description of logical structure of database
B)
Addition of new structures in the database system
C)
Manipulation & processing of database
D)
Definition of physical structure of database system
DML stands for Data Manipulation Language. It is used to retrieve, insert, update, and delete data in a database, i.e., for manipulation and processing of database records. Option (a) refers to DDL/DB schema description, option (b) is about adding structures, and option (d) refers to physical database definition, not DML.
Statement and branch coverage metrics are part of
A)
Analysis Model
B)
Testing
C)
Design Model
D)
Source code
Statement coverage and branch coverage are code coverage metrics used during software testing to measure how much of the program has been executed by test cases. They are not part of the analysis model or design model. While they are applied to source code, they specifically belong to the testing phase as testing metrics.
__________ is a black box testing method
A)
Boundary value analysis
B)
Basic path testing
C)
Code path analysis
D)
None of these
Boundary value analysis is a black box testing technique because it tests the input/output behavior of the software without looking at the internal code. It focuses on values at the boundaries of input ranges, where defects are most likely. Basic path testing and code path analysis are white box techniques because they depend on the internal structure and logic of the program. Therefore, the correct answer is Boundary value analysis.
A TCP/IP application service that converts user-friendly names to IP addresses is
A)
Browser
B)
Web-server
C)
Domain name system
D)
Domain name suit
The TCP/IP service that translates human-friendly domain names like www.example.com into IP addresses is the Domain Name System (DNS). It acts like the Internet's phonebook. Browser and web-server are not name-to-IP translation services, and 'Domain name suit' is an incorrect term.
The total participation by entities is represented in E-R diagram as
A)
Dashed line
B)
Double line
C)
Double rectangle
D)
Circle
In an E-R diagram, total participation means every entity instance must participate in the relationship. It is represented by a double line connecting the entity set to the relationship set. A dashed line is not used for total participation, a double rectangle represents a weak entity, and a circle is used for attributes.
Which of the following is the process of increasing redundancy in the database either for convenience or to improve performance?
A)
Normalisation
B)
Optimisation
C)
Dependency
D)
Denormalisation
Denormalisation is the process of intentionally adding redundancy to a database to improve read performance or simplify queries. Normalisation does the opposite: it reduces redundancy and avoids update anomalies. Optimisation is a general performance-improvement term, not specifically about increasing redundancy. Dependency refers to a relationship between attributes, not the process described here.
Which of the following is a project scheduling method that can be applied to software development?
A)
PERT
B)
CMM
C)
CPM
D)
Both (a) and (c)
PERT (Program Evaluation and Review Technique) and CPM (Critical Path Method) are both project scheduling techniques used to plan, sequence, and monitor project activities, including software development projects. CMM (Capability Maturity Model) is not a scheduling method; it is a process maturity framework for assessing and improving software process capability. Therefore, the correct answer is Both (a) and (c).
In DFDs, user interactions with the system is denoted by
A)
Circle
B)
Arrow
C)
Rectangle
D)
Triangle
In a Data Flow Diagram (DFD), the external entity or user interacting with the system is represented by a rectangle. Arrows show data flow, circles/ovals usually represent processes in some notations, and triangles are not used for user interaction in standard DFD symbols.
In CSMA/CD the transmission is deferred for a period of time called
A)
Interpacket Space
B)
Interframe Space
C)
Intermessage space
D)
Transmission delay
In CSMA/CD, after the medium becomes idle, a station waits for a short deferment period before transmitting. This waiting time is commonly referred to as the interpacket space. The other options are not the standard term used for CSMA/CD deferment.
In OSI model dialogue control and token management are responsibilities of
A)
Session Layer
B)
Network layer
C)
Transport layer
D)
Data link layer
In the OSI model, the Session Layer is responsible for establishing, managing, and terminating sessions between applications. It also handles dialogue control and token management. The Network layer deals with routing, the Transport layer with end-to-end delivery, and the Data Link layer with node-to-node transfer and error control.
The aim of software engineering is to produce software that is
A)
Fault-free
B)
Delivered on time, Delivered within budget
C)
Satisfies users’ needs
D)
All of these
Software engineering aims to develop software that is reliable and as fault-free as possible, delivered on time and within budget, and most importantly satisfies users’ needs. Since all three statements are valid goals, the correct answer is 'All of these'.
A _____ is a device that forwards packets between networks by processing the routing information included in the packet.
A)
Bridge
B)
Router
C)
Firewall
D)
Switch
A router forwards packets between different networks by examining the routing information in the packet and choosing the best path. A bridge and a switch mainly forward frames within a LAN, while a firewall filters traffic based on security rules rather than routing packets between networks.
A query in the tuple relational calculus is expressed as
A)
{t | P() | t}
B)
{P(t) | t}
C)
{t | P(t)}
D)
All of these
In tuple relational calculus, a query is written in the form { t | P(t) }, where t is a tuple variable and P(t) is a predicate that specifies the condition tuples must satisfy. Option (a) and (b) are not the standard tuple relational calculus notation, so they are incorrect. Therefore, the correct answer is (c).
In SQL the statement select * from R, S is equivalent to
A)
Select * from R natural join S
B)
Select * from R cross join S
C)
Select * from R union join S
D)
Select * from R inner join S
In SQL, `SELECT * FROM R, S` lists two tables in the FROM clause without any join condition. This produces the Cartesian product of R and S, which is exactly a CROSS JOIN. A NATURAL JOIN or INNER JOIN requires matching conditions, and UNION combines rows vertically rather than forming all pairwise combinations.
The main design activities in the software design process are: i) System specification, ii) interface design, iii) Component design, iv) algorithm design
A)
ii, iii and iv only
B)
i, ii and iii only
C)
i, iii and iv only
D)
All i, ii, iii and iv
In software engineering, the main design activities are interface design, component design, and algorithm design. System specification is not a design activity; it is part of requirements/specification before design begins. Therefore, the correct set is ii, iii and iv only.
A quantitative measure of the degree to which a system, component, or process posses a given attribute
A)
Measure
B)
Measurement
C)
Metric
D)
None of these
In software engineering, a **metric** is defined as a quantitative measure of the degree to which a system, component, or process possesses a given attribute.
- **Measure** is a general term, not the specific software engineering definition.
- **Measurement** is the act or result of measuring, but the standard term for the quantitative indicator itself is **metric**.
- Therefore, the correct answer is **(c) Metric**.
Coupling is a qualitative indication of the degree to which a module
A)
can be written more compactly.
B)
focuses on just one thing.
C)
is able to complete its function in a timely manner.
D)
is connected to other modules and the outside world.
Coupling measures the degree of interdependence between modules. A module with high coupling is strongly connected to other modules or external components, while low coupling is preferred in good software design. Option (d) correctly describes coupling. Option (b) refers to cohesion, not coupling.
The model in which the requirements are implemented by category is
A)
Evolutionary Development Model
B)
Waterfall Model
C)
Prototyping
D)
Iterative Enhancement Model
In the Iterative Enhancement Model, the system is developed in small increments, and requirements are implemented category-wise or feature-wise in successive versions. This allows partial implementation and gradual refinement. The Waterfall Model follows a linear sequence of phases, the Prototyping Model focuses on building a prototype for requirement clarification, and the Evolutionary Development Model is broader but not specifically described as implementing requirements by category.