# L&T Technology Services Interview Questions with Answers

8 previously-asked interview questions from L&T Technology Services's hiring process, each with the correct answer and a worked explanation. Written against the company's actual test pattern.

_Source: Astra (https://useastra.in). Updated 2026-09-05._

### 1. What is the difference between RAM and ROM?

**Answer:** RAM is volatile read-write memory used for temporary runtime data and loses contents on power off. ROM is non-volatile memory that retains contents without power and typically stores firmware or boot code. RAM is faster and rewritable; ROM is mostly read only.

**Explanation:** RAM: volatile, read-write. ROM: non-volatile, mostly read only.

### 2. What is an embedded system?

**Answer:** An embedded system is a dedicated computer built into a larger device to perform a specific function, combining a microcontroller or microprocessor with software and often real time constraints. Examples include washing machines, cars, and medical devices.

**Explanation:** A dedicated computer built into a device for a specific task.

### 3. What is the difference between a stack and a queue?

**Answer:** A stack is Last In First Out: the most recently added element is removed first. A queue is First In First Out: elements are removed in the order they were added. Stacks suit backtracking and recursion; queues suit scheduling and buffering.

**Explanation:** Stack is LIFO; queue is FIFO.

### 4. State and explain Ohms law.

**Answer:** Ohms law states that the current through a conductor between two points is directly proportional to the voltage and inversely proportional to the resistance, expressed as V = I * R. It is fundamental to analysing electrical circuits.

**Explanation:** V = I * R; current is proportional to voltage, inverse to resistance.

### 5. What is the difference between C and Embedded C?

**Answer:** C is a general purpose language for many platforms. Embedded C is C with extensions and conventions for microcontrollers, using hardware specific headers, fixed-width types, direct register access, and keywords like volatile, often without a full standard library or operating system.

**Explanation:** Embedded C is C adapted for microcontroller and hardware programming.

### 6. What is a real time operating system (RTOS)?

**Answer:** An RTOS is an operating system designed to process tasks within strict timing deadlines, offering deterministic scheduling. Hard real time guarantees deadlines (for example airbags), while soft real time tolerates occasional misses (for example video). It is common in embedded devices.

**Explanation:** An OS that meets strict timing deadlines deterministically.

### 7. Tell me about yourself.

**Answer:** Give a concise 60 to 90 second overview: your branch and degree, core strengths (embedded, hardware, or software), a relevant project, and why LTTS interests you. Keep it structured and role-relevant.

**Explanation:** Structured pitch: background, strengths, project, fit.

### 8. Why do you want to join L&T Technology Services?

**Answer:** Mention LTTS position as a pure play engineering and R&D services firm across automotive, aerospace, medical, and industrial domains, and the chance to work on real engineering products. Tie it to your branch and interests.

**Explanation:** Pure-play engineering R&D across strong domains.

More L&T Technology Services preparation, including the full recruitment process: https://useastra.in/campus/ltts