40+ L2 Engineer Interview Questions and Answers

Radiography testing (RT) and ultrasonic testing (UT) are both non-destructive testing methods used to detect flaws in materials.

• Radiography testing uses X-rays or gamma rays to create an image of the internal structure of an object, while ultrasonic testing uses high-frequency sound waves.

• RT is typically used for thicker materials and can detect both surface and subsurface defects, while UT is more commonly used for thinner materials and can only detect surface defects.

• RT pro...read more

Design patterns are reusable solutions to common software problems.

• Creational patterns: Singleton, Factory, Abstract Factory, Builder

• Structural patterns: Adapter, Bridge, Composite, Decorator, Facade, Flyweight, Proxy

• Behavioral patterns: Chain of Responsibility, Command, Interpreter, Iterator, Mediator, Memento, Observer, State, Strategy, Template Method, Visitor

Essential variables are crucial for the functioning of a system, while non-essential variables are not necessary but may provide additional information.

• Essential variables are required for the system to operate correctly.

• Non-essential variables are not necessary for the system's basic functionality.

• Essential variables are typically directly related to the core purpose of the system.

• Non-essential variables may provide supplementary data or enhance the system's performance.

• For ...read more

Sample classes for Spring Boot entity, service, and controller layers with annotations

• Create entity classes with @Entity and @Id annotations

• Create service classes with @Service annotation and inject repository classes with @Autowired annotation

• Create controller classes with @RestController and @RequestMapping annotations

• Use @GetMapping, @PostMapping, @PutMapping, and @DeleteMapping annotations for HTTP methods

• Use @RequestBody and @PathVariable annotations for request paramete...read more

Hash map is an internal data structure that maps keys to values. Comparator is used to compare objects for sorting.

• Hash map uses a hash function to map keys to indices in an array

• Comparator is used to compare objects for sorting in collections like TreeSet or TreeMap

• Example of hash map implementation in Java: HashMap

• Example of using a comparator in Java: Collections.sort(list, comparator)

No, RT cannot replace UT examination.

• RT (Radiographic Testing) and UT (Ultrasonic Testing) are two different non-destructive testing methods used in engineering.

• RT uses X-rays or gamma rays to inspect the internal structure of an object, while UT uses sound waves to detect flaws or measure thickness.

• Each method has its own advantages and limitations, and they are often used in combination to ensure comprehensive inspection.

• For example, RT is effective for detecting internal d...read more

The type of bearing required for a machine drive is selected based on factors such as load, speed, lubrication, and operating conditions.

• Consider the load and speed requirements of the machine drive

• Choose between ball bearings, roller bearings, or plain bearings based on the application

• Take into account the lubrication method and maintenance requirements

• Consider the operating conditions such as temperature, vibration, and alignment

OOPs concepts are used in my project for creating reusable and modular code.

• I use inheritance to create a base class for common functionalities and then derive specific classes from it.

• Encapsulation is used to hide the internal implementation details of a class and only expose necessary methods and properties.

• Polymorphism allows me to use a single interface to represent different data types or objects.

• Abstraction helps in defining the structure of classes without specifying t...read more

Yes, I managed a CI/CD pipeline in my project.

• Setting up automated testing was a challenge due to compatibility issues.

• Integrating different tools and technologies caused some delays.

• Ensuring smooth deployment across multiple environments required careful planning.

WPS stands for Welding Procedure Specification and PQR stands for Procedure Qualification Record.

• WPS is a document that provides detailed instructions on how to perform a specific welding procedure.

• It includes information on welding parameters, materials, pre-weld and post-weld treatments, etc.

• PQR is a record that documents the actual results of a welding procedure qualification test.

• It includes details of the test, such as the welding process used, materials, test results, e...read more

Safety in chemical process design and operation is prioritized through thorough risk assessments, implementing safety protocols, providing proper training, and continuous monitoring.

• Conducting thorough risk assessments to identify potential hazards and risks in the chemical process

• Implementing safety protocols and procedures to mitigate risks and prevent accidents

• Providing proper training to all personnel involved in the process to ensure they are aware of safety measures and...read more

During a line down situation, managing line output involves troubleshooting, identifying the root cause, implementing solutions, and communicating with stakeholders.

• Quickly troubleshoot to identify the root cause of the line down

• Implement temporary solutions to restore line output if possible

• Communicate with relevant teams and stakeholders to keep them informed

• Work on permanent solutions to prevent future line down situations

• Document the incident and steps taken for future re...read more

Software used in FTTx design

• AutoCAD for creating network diagrams

• Geographic Information System (GIS) for mapping

• Optical Network Design and Planning (ONDAP) for fiber optic network planning

• FiberPlanIT for designing and optimizing FTTx networks

• Google Earth for visualizing network routes

• Bentley Fiber for designing and documenting fiber networks

The direction of current flow is opposite to the direction of electron flow due to historical convention.

• The concept of current flow was developed before the discovery of electrons.

• Benjamin Franklin proposed the convention of positive charge carriers, which led to the opposite direction of current flow.

• In reality, electrons are negatively charged and flow from the negative terminal to the positive terminal of a power source.

• However, the convention of current flow from positiv...read more

Yes, QAP/ITP stands for Quality Assurance Plan/Inspection and Test Plan.

• QAP/ITP is a document that outlines the quality assurance and inspection procedures for a project or product.

• It includes details about the tests to be conducted, acceptance criteria, and responsibilities of different stakeholders.

• QAP/ITP ensures that the project or product meets the required quality standards and specifications.

• For example, in construction projects, a QAP/ITP may specify the tests to be p...read more

To handle waste material on site, proper planning, monitoring, and training of staff are essential. Concrete temperature tests are conducted to ensure the quality and strength of the concrete.

• Implement a waste management plan to track and minimize material wastage on site

• Train staff on proper handling and storage of materials to prevent wastage

• Regularly monitor material usage and wastage to identify areas for improvement

• Reuse or recycle materials whenever possible to reduce w...read more

STP is a network protocol that prevents loops in Ethernet networks. OSPF and BGP are routing protocols used to exchange routing information.

• STP (Spanning Tree Protocol) is used to prevent loops in Ethernet networks by creating a loop-free logical topology.

• STP works by electing a root bridge and calculating the shortest path to the root bridge for each network segment.

• OSPF (Open Shortest Path First) is an interior gateway protocol used for routing within an autonomous system.

• O...read more

No, primary keys should not be deleted as they uniquely identify each record in a database.

• Primary keys are essential for maintaining data integrity and ensuring uniqueness of records.

• Deleting a primary key can lead to data inconsistencies and errors in the database.

• If a primary key needs to be changed, it is better to update it rather than delete it.

I have automated approximately 500 test cases.

• I have automated test cases for critical functionalities to ensure robustness.

• I have automated regression test cases to save time and effort during testing.

• I have automated boundary test cases to ensure the system handles extreme scenarios.

• I have automated negative test cases to validate error handling.

• I have automated performance test cases to assess system response under load.

• Example: Automated login test cases, data validation ...read more

Difference and least count of measuring instruments

• Difference: Range of values that can be measured by the instrument

• Least count: Smallest change in the quantity being measured that can be detected by the instrument

• Examples: Vernier caliper - Difference: 0-150mm, Least count: 0.02mm; Micrometer screw gauge - Difference: 0-25mm, Least count: 0.01mm

Mapping temperature controlled rooms involves creating a visual representation of temperature distribution within the space.

• Use sensors to collect temperature data at various points in the room

• Create a map or diagram showing temperature gradients and hot/cold spots

• Implement HVAC systems to regulate temperature based on mapping results

Quality of mesh in FEM is checked by examining element shapes, aspect ratios, and convergence of results.

• Check element shapes to ensure they are not distorted or skewed

• Evaluate aspect ratios to ensure they are within acceptable limits

• Verify convergence of results by refining the mesh and comparing results

Windows 7 and 10 are different versions of the Windows operating system.

• Windows 10 has a more modern and user-friendly interface compared to Windows 7.

• Windows 10 has better performance and improved security features.

• Windows 10 has a virtual assistant called Cortana, which is not available in Windows 7.

• Windows 10 supports newer hardware and technologies that Windows 7 may not.

• Windows 10 receives regular updates and support from Microsoft, while Windows 7 has reached its end of...read more

The different terminals of a MOSFET are the gate, source, and drain.

• The gate terminal controls the flow of current between the source and drain.

• The source terminal is where the current enters the MOSFET.

• The drain terminal is where the current exits the MOSFET.

• The gate-source voltage determines the conductivity of the channel between the source and drain.

• Examples of MOSFETs include enhancement-mode and depletion-mode MOSFETs.

Leakage current in CMOS refers to the small amount of current that flows through the transistors when they are in the off state.

• Leakage current occurs due to the imperfect insulation between the source and drain terminals of the transistors.

• It is an undesirable phenomenon as it leads to power dissipation and can affect the performance and reliability of CMOS circuits.

• Leakage current can be categorized into subthreshold leakage, gate leakage, and junction leakage.

• Subthreshold ...read more

Drop means to remove a database object, while delete means to remove data from a table.

• Drop is used to remove an entire database object like a table, view, or database itself.

• Delete is used to remove specific rows of data from a table.

• Drop operation is irreversible and can lead to loss of data, while delete operation can be rolled back if within a transaction.

• Example: DROP TABLE employees; DELETE FROM employees WHERE age > 50;

The erection sequence of a boiler and ESP involves several steps to ensure proper installation and functioning.

• The foundation for the boiler and ESP must be prepared and laid out.

• The boiler and ESP components are then assembled and installed on the foundation.

• The piping and ductwork are connected to the boiler and ESP.

• The electrical and control systems are installed and connected.

• The boiler and ESP are tested and commissioned to ensure proper functioning.

• The final step involv...read more

Interface defines a contract while abstract class provides partial implementation.

• Interface only contains method signatures while abstract class can have both abstract and non-abstract methods.

• A class can implement multiple interfaces but can only inherit from one abstract class.

• Interfaces are used for achieving multiple inheritance while abstract classes are used for code reusability.

• An interface cannot have a constructor while an abstract class can have one.

• An interface can...read more

Triggers are special stored procedures in databases that are automatically executed or fired when certain events occur.

• Triggers are used to maintain data integrity by enforcing business rules or automating actions.

• They can be set to execute before or after an INSERT, UPDATE, or DELETE operation on a table.

• Examples of triggers include auditing changes to a table, updating a related table when a record is inserted, or enforcing constraints.

Pneumatics and hydraulics systems are used in engineering for power transmission and control.

• Pneumatics systems use compressed air to transmit power, commonly used in industries for automation and control.

• Hydraulics systems use pressurized liquid (usually oil) to transmit power, commonly used in heavy machinery like excavators and hydraulic presses.

• Pneumatics systems are generally faster but less powerful than hydraulics systems.

• Hydraulics systems are more precise and can han...read more

I have 5 years of experience in the telecom industry.

• Worked as a network engineer for a major telecom company

• Managed and maintained network infrastructure

• Implemented new technologies such as 5G and VoLTE

• Troubleshot and resolved network issues

• Collaborated with cross-functional teams to ensure smooth operations

A Book Management System to organize and track books in a library or personal collection.

• Create a database to store book information such as title, author, genre, and availability status.

• Implement a user interface for users to search, borrow, return, and add new books.

• Include features like book recommendations, reviews, and notifications for due dates.

• Utilize barcode scanning or ISBN lookup for easy book entry and tracking.

MTTR is the average time to repair a failed system, while MTBF is the average time between failures.

• MTTR measures downtime and repair time, while MTBF measures reliability and uptime.

• MTTR is a measure of maintainability, while MTBF is a measure of reliability.

• MTTR is calculated as total downtime divided by number of failures, while MTBF is calculated as total uptime divided by number of failures.

• For example, if a system has an MTBF of 1000 hours and an MTTR of 2 hours, it mea...read more

IPv4 uses 32-bit addresses while IPv6 uses 128-bit addresses.

• IPv4 addresses are written in decimal format (e.g. 192.168.1.1) while IPv6 addresses are written in hexadecimal format (e.g. 2001:0db8:85a3:0000:0000:8a2e:0370:7334).

• IPv4 supports around 4.3 billion unique addresses, while IPv6 supports an astronomical number of unique addresses (2^128).

• IPv4 uses ARP (Address Resolution Protocol) for mapping IP addresses to MAC addresses, while IPv6 uses NDP (Neighbor Discovery Prot...read more

MPLS stands for Multiprotocol Label Switching, a technique used in telecommunications networks to direct data packets along predefined paths.

• MPLS is a protocol used to speed up and shape network traffic.

• It operates at layer 2.5 of the OSI model, between traditional layer 2 (Data Link Layer) and layer 3 (Network Layer).

• MPLS uses labels to make forwarding decisions, allowing for faster and more efficient routing.

• It is commonly used by service providers to offer quality of servi...read more

IP stands for Internet Protocol, a set of rules governing the format of data sent over the internet.

• IP addresses are unique identifiers assigned to devices connected to a network.

• There are two versions of IP - IPv4 and IPv6.

• IP packets contain information such as source and destination addresses, as well as data payload.

• IP routing is the process of forwarding packets from one network to another.

• Subnetting allows for the division of IP networks into smaller subnetworks.

OSI layers refer to the seven layers in the OSI model that define the functions of a network protocol stack.

• The OSI (Open Systems Interconnection) model is a conceptual framework used to understand how different networking protocols interact.

• There are seven layers in the OSI model, each with its own specific functions and responsibilities.

• The layers are: Physical, Data Link, Network, Transport, Session, Presentation, and Application.

• Each layer communicates with the layers abo...read more

An inductor is a passive electronic component that stores energy in a magnetic field when current flows through it.

• Inductors are typically made of a coil of wire wound around a core material.

• They are used in electronic circuits to control the flow of current and store energy.

• Inductors can be found in various applications such as power supplies, filters, and oscillators.

• They are measured in units called henries (H).

• Inductors oppose changes in current and can cause delays or ph...read more

Ohm's law states that the current flowing through a conductor is directly proportional to the voltage applied across it and inversely proportional to its resistance.

• Ohm's law is expressed as V = IR, where V is the voltage, I is the current, and R is the resistance.

• It helps in understanding the relationship between voltage, current, and resistance in an electrical circuit.

• For example, if the voltage across a resistor is increased, the current flowing through it will also incre...read more

Manual testing of test involves executing test cases without the use of automation tools.

• Manual testing is done by human testers without the use of automation tools.

• Test cases are executed step by step to ensure the software functions as expected.

• Manual testing is time-consuming but can uncover user experience issues that automated tests may miss.

Speed and feed formula is used in machining to determine the optimal cutting parameters for a specific material and tool.

• Speed and feed formula calculates the spindle speed (RPM) and feed rate (IPM) for a given material and tool combination.

• The formula takes into account factors such as material type, tool diameter, and desired surface finish.

• For example, the formula for calculating spindle speed is: RPM = (CS x 4) / D, where CS is cutting speed and D is tool diameter.

Temperature mapping involves monitoring and recording temperatures in different areas to ensure proper temperature control.

• Use temperature sensors to collect data

• Create a map of the area with temperature readings

• Analyze the data to identify any temperature variations

• Implement measures to regulate temperature if needed

LINQ (Language Integrated Query) is a feature in C# that allows for querying data from different data sources using a SQL-like syntax.

• LINQ allows for querying data from collections, databases, XML, and more.

• It provides a set of standard query operators like Where, Select, OrderBy, GroupBy, etc.

• LINQ queries are written in a declarative syntax, making code more readable and maintainable.

• Example: var result = from num in numbers where num % 2 == 0 select num;

An HVAC system is a heating, ventilation, and air conditioning system that controls the temperature, humidity, and air quality in a building.

• Consists of a furnace or boiler for heating

• Includes a central air conditioner for cooling

• Utilizes ductwork to distribute air throughout the building

• May have a thermostat to control temperature settings

• Can include air filters for improving indoor air quality

Java 8 introduced new features for working with threads, such as CompletableFuture and parallel streams.

• Java 8 introduced CompletableFuture class for asynchronous programming.

• Parallel streams in Java 8 allow for easy parallelization of operations on collections.

• New methods like `join()` and `thenApply()` were added to the Thread class in Java 8.

Interest in output refers to the level of curiosity and enthusiasm a person has towards the end result or outcome of a project or task.

• Interest in output can drive motivation and productivity in completing tasks.

• It involves being invested in the final outcome and taking pride in the results.

• Individuals with high interest in output are more likely to pay attention to details and strive for excellence.

• Example: A software engineer who is passionate about creating user-friendly i...read more