# Set 1 (Chaitra, 2080)

## Short Questions 60 Marks

#### 1. What is the dimensional formula of kinematic viscosity?

1. $$M^2LT^{-1}$$
2. $$\[L^2 T^{-1}]$$
3. $$LT^{-1}$$
4. $$LT^{-2}$$

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**Answer:** **2.**&#x20;

* The correct dimensional formula is:

  $$\[\nu] = L^{2} T^{-1}$$
* Explanation: Kinematic viscosity $$\nu$$ is the ratio of dynamic viscosity to density.
* Dynamic viscosity $$\mu$$:

  $$\[\mu] = M L^{-1} T^{-1}$$
* Density $$\rho$$:

  $$\[\rho] = M L^{-3}$$
* Therefore,

  $$\[\nu] = \frac{\[\mu]}{\[\rho]} = \frac{M L^{-1} T^{-1}}{M L^{-3}} = L^{2} T^{-1}$$

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#### 2. Who appoints the chairman of Nepal Engineering Council?

1. Government of Nepal
2. Central executive committee of NEC
3. NEC members
4. Elected from Nepali Engineers

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**Answer:** **1) Government of Nepal**

**Explanation:** As per the Nepal Engineering Council Act, the **Government of Nepal** appoints the chairman.

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#### 3. What is not an effective method to avoid corrosion?

1. Electroplating
2. Metal plating
3. Colour painting
4. Enameling

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**Answer:** **3) Colour painting**

**Explanation:** Colour painting provides only a temporary physical barrier and is less effective for long-term corrosion protection. Methods like electroplating, metal plating, and enameling provide more durable and sacrificial or impermeable barriers.

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#### 4. What does machine code M06 refer to?

1. Tool stop
2. Tool change
3. Coolant off
4. Coolant on

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**Answer:** **2) Tool change**

**Explanation:** In standard CNC (Computer Numerical Control) programming, the **M06** code is used to command a **tool change**.

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#### 5. The work done in dropping an object from slanted height will be \_\_\_\_\_\_ compared to dropping in vertical height.

1. Equal
2. Less
3. More
4. Zero

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**Answer:** **1) Equal**

**Explanation:** The work done by the gravitational force is **path-independent**. It depends only on the vertical displacement (height). Therefore, the work done is the same whether the path is slanted or vertical.

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#### 6. What type of maintenance includes routine check up and inspection of equipment?

1. Preventive
2. Predictive
3. Breakdown
4. Periodic

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**Answer:** **1) Preventive**

**Explanation:** **Preventive Maintenance (PM)** involves scheduled, routine inspections, servicing, and part replacements to prevent equipment failure before it occurs.

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#### 7. Military organization is an example of:

1. Staff organization
2. Functional organization
3. Line organization
4. Line and staff organization

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**Answer:** **4) Line and staff organization**

**Explanation:** Military organizations typically use a **line and staff structure**. Line officers (e.g., commanders) have direct authority and responsibility for operations, while staff officers (e.g., logistics, intelligence) provide specialized advice and support.

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#### 8. The term "cost down" refers to:

1. Reducing cost
2. Sales cost
3. Production cost
4. Wages and salary

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**Answer:** **1) Reducing cost**

**Explanation:** "Cost down" is a business and engineering term that refers to systematic efforts and strategies aimed at **reducing the overall cost** of a product or process.

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#### 9. Which of the following is true for phase change of saturated liquid to vapour?

1. $$P > P\_{sat}$$ and $$T > T\_{sat}$$
2. $$P\_{sat} > P$$ and $$T\_{sat} > T$$
3. $$P = P\_{sat}$$ and $$T = T\_{sat}$$
4. $$P < P\_{sat}$$ and $$T < T\_{sat}$$

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**Answer:** **3)** $$P = P\_{sat}$$ **and** $$T = T\_{sat}$$

**Explanation:** For a pure substance, the phase change from saturated liquid to saturated vapour occurs at constant temperature and pressure, known as the saturation pressure $$(P\_{sat})$$ and saturation temperature $$(T\_{sat})$$.

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#### 10. What does the term A/F, 7%, 8 does not refer to?

1. The time is 8 years
2. The percentage rate is 7%
3. Calculating A when F is given
4. Calculating F when A is given

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**Answer:** **4) Calculating F when A is given**

**Explanation:** In engineering economics, the notation **(A/F, i, n)** represents the **Sinking Fund Factor**. It is used to **find the uniform annual series (A) that must be set aside to accumulate a given future sum (F)** at an interest rate (i) over (n) periods. It does NOT refer to finding F given A.

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#### 11. Which type of working process is used for producing containers (like plastic jars)?

1. Extrusion
2. Blow Moulding
3. Die casting
4. Rolling

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**Answer:** **2) Blow Moulding**

**Explanation:** Hollow plastic containers such as bottles and jars are commonly manufactured using **blow molding**, where a heated plastic parison is inflated inside a mold.

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#### 12. Which type of working process produces better finish in materials?

1. Direct extrusion
2. Indirect extrusion
3. Rolling
4. None

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**Answer:** **2) Indirect extrusion**

**Explanation:** **Indirect extrusion** (or backward extrusion) generally produces a better surface finish than direct extrusion because there is no relative motion between the billet and the container wall, reducing friction and surface defects.

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#### 13. What is not a common type of welding defect?

1. Cracks
2. Porosity
3. Solid inclusion
4. Cold shuts

*Options:* a. 1 and 3 b. 1 and 4 c. 1, 3 and 4 d. 2, 3 and 4

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**Answer:** **b. 1 and 4**

**Explanation:**

* **Cracks** are a common welding defect.
* **Cold shuts** are a defect associated with **casting** processes, not welding. Therefore, the combination that includes "cold shuts" (option 4) as a non-welding defect is correct.

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#### 14. How does ionic crystal fracture?

1. Creep type
2. Fatigue type
3. Shear type
4. Brittle type

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**Answer:** **4) Brittle type**

**Explanation:** Ionic crystals (e.g., NaCl) have strong, directional ionic bonds that restrict dislocation movement. They typically fail with little to no plastic deformation, resulting in a **brittle fracture**.

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#### 15. What is used to represent the quality of a grinding wheel?

1. Vickers hardness number
2. Brinell hardness number
3. Rockwell hardness number
4. Letter of alphabets

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**Answer:** **4) Letter of alphabets**

**Explanation:** The **grade** or hardness of a grinding wheel (its ability to hold abrasive grains) is indicated by a **letter from A (soft) to Z (hard)**.

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#### 16. Which is not a liquid lubricant?

1. Palm oil
2. Grease
3. Mustard oil
4. Vegetable oil

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**Answer:** **2) Grease**

**Explanation:** Grease is a **semi-solid lubricant** consisting of a base oil thickened with a soap or other agent. Palm oil, mustard oil, and vegetable oil are all liquid lubricants.

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#### 17. How much area will a two-stroke engine occupy compared to a four-stroke engine for same power generation?

1. Same
2. Less
3. More
4. Cannot be said

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**Answer:** **2) Less**

**Explanation:** A two-stroke engine produces a power stroke every revolution, while a four-stroke engine produces one every two revolutions. Therefore, for the same power output, a two-stroke engine is generally more compact and occupies **less space**.

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#### 18. For gears, how is comparison done between bending stress and contact stress?

1. Bending stress is compared to allowable bending stress; contact stress is compared to allowable contact stress.
2. Bending stress is always greater than contact stress.
3. Contact stress is only relevant for plastic gears.
4. They are compared using the same fatigue limit.

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**Answer:** **1) Bending stress is compared to allowable bending stress; contact stress is compared to allowable contact stress.**

**Explanation:** Gear design involves two primary failure modes: **bending failure** at the tooth root and **surface pitting (contact) failure**. Each is governed by its own stress equation (Lewis equation for bending, Hertzian contact stress) and material strength property (allowable bending stress and allowable contact stress, respectively).

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#### 19. If N2 is greater than N1, what would be the action of a transformer?

1. Step up
2. Step down
3. Same voltage
4. Does not depend

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**Answer:** **1) Step up**

**Explanation:** The transformer voltage ratio is approximately equal to the turns ratio.

If the secondary turns $$(N\_2)$$ are greater than the primary turns $$(N\_1)$$, then the secondary voltage $$(V\_2)$$ will be greater than the primary voltage $$(V\_1)$$. This is a **step-up** transformer.

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#### 20. Oscillator is different from amplifier in:

1. Has more gain
2. Does not require DC
3. Both are same
4. Has constant signal

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**Answer:** **2) Does not require DC** *(clarification: Does not require an external AC input signal)*

**Explanation:** The fundamental difference is that an **amplifier** requires an external input signal to amplify, while an **oscillator** generates its own periodic output signal without any external AC input, using positive feedback and a DC power source.

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#### 21. The first/detail drawing of the system is:

1. Draft
2. Prototype
3. Model
4. Print

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**Answer:** **1) Draft**

**Explanation:** A **draft** or **draft drawing** is the initial, detailed technical drawing that specifies the dimensions, tolerances, and geometry of a part or system.

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#### 22. The time between ordering and receiving of the order is:

1. Lead time
2. Storing time
3. Material handling time
4. None

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**Answer:** **1) Lead time**

**Explanation:** In supply chain and operations management, **lead time** is the total time elapsed from the placement of an order until its receipt and availability for use.

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#### 23. Ethics refers to:

1. Rightness and wrongness in profession
2. Moral values of society
3. Individual goals
4. None

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**Answer:** **1) Rightness and wrongness in profession**

**Explanation:** Professional ethics refers to the principles and standards that guide conduct and decision-making within a specific profession, defining what is considered right and wrong behavior in that context.

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#### 24. What does CAR represent?

1. Contract all risk
2. Consultant all risk
3. Contractor's all risk
4. None

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**Answer:** **3) Contractor's all risk**

**Explanation:** **CAR** stands for **Contractor's All Risk** insurance. It is a type of policy that provides coverage for damage to the construction works, materials, and equipment, as well as third-party liability, during a construction project.

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#### 25. Relation between damping, stiffness and mass is:

1. $$W^2 = k / m$$
2. $$W = k / m$$
3. $$K = w^\* m^2$$
4. $$K = w^2 \* m^2$$

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**Answer:** **1)** $$W^2 = k / m$$

**Explanation:** For a simple undamped mass-spring system, the natural angular frequency $$( \omega\_n )$$ is given by:

where $$k$$ is the stiffness and $$m$$ is the mass.

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#### 26. For liquid to slip in a container when it suddenly stops, the acceleration is proportional to:

1. g
2. g/2
3. 2g
4. 3g/2

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**Answer:** **1) g**

**Explanation:** When a container of liquid decelerates suddenly, the free surface of the liquid will experience a slope. The condition for the liquid to "slip" or surge is related to the deceleration of the container. For the liquid to just begin to spill or surge over the edge, the horizontal deceleration $$(a)$$ is typically equal to the gravitational acceleration $$(g)$$ multiplied by the ratio of tank dimensions. For a simple case (like a rectangular tank), the critical deceleration is often $$a = g$$. **g** is the most directly proportional factor.

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#### 27. What is used to calibrate slip gauge?

1. Slip base
2. Interferometer
3. Micrometer
4. Height Gauge

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**Answer:** **2) Interferometer**

**Explanation:** Slip gauges (or gauge blocks) are calibrated to very high precision using an **optical interferometer**, which compares the length of the gauge to the wavelength of light.

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#### 28. What is used to measure the inclination of a surface?

1. Collimator
2. Slip gauge
3. Micrometer
4. Vernier caliper

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**Answer:** **1) Collimator**

**Explanation:** A **collimator** is an optical device used to measure small angles and the alignment or inclination of surfaces, often used with an autocollimator for precise angular measurements.

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#### 29. Eddy current is used to measure:

1. Defects
2. Smoothness
3. Dimensions
4. None

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**Answer:** **1) Defects**

**Explanation:** **Eddy Current Testing (ECT)** is a non-destructive testing method primarily used to detect surface and near-surface **defects** (like cracks) in conductive materials by monitoring changes in induced eddy currents.

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#### 30. Who was the first to describe the term 'boundary layer'?

1. Reynold
2. Prandtl
3. Newton
4. Lagrange

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**Answer:** **2) Prandtl**

**Explanation:** The concept of the **boundary layer** was first introduced by **Ludwig Prandtl** in 1904, revolutionizing the study of fluid dynamics by separating flow into a thin viscous layer near surfaces and an inviscid outer flow.

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#### 31. Expansion process in Rankine cycle is:

1. Isentropic
2. Isobaric
3. Isochoric
4. Isothermal

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**Answer:** **1) Isentropic**

**Explanation:** In the ideal Rankine cycle, the working fluid expands through the turbine **isentropically** (at constant entropy), converting thermal energy into work.

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#### 32. The diameter of the shank of the rivet depends upon?

1. Thickness
2. Yield strength
3. Length
4. None

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**Answer:** **1) Thickness**

**Explanation:** The shank diameter of a rivet is primarily chosen based on the **total thickness of the plates** being joined to ensure sufficient shear strength.

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#### 33. The longitudinal strain of the fibre depends upon:

1. Strength of fibre
2. Orientation of fibre
3. Diameter of fibre
4. None

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**Answer:** **2) Orientation of fibre**

**Explanation:** In composite materials, the strain experienced by a fiber under load is highly dependent on its **orientation** relative to the direction of the applied load, as described by the rule of mixtures and transformation equations.

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#### 34. The boiling temperature of water is:

1. $$312^{\circ}F$$
2. $$212^{\circ}F$$
3. $$150^{\circ}F$$
4. $$320^{\circ}F$$

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**Answer:** **2)** $$212^{\circ}F$$

**Explanation:** At standard atmospheric pressure (1 atm), the boiling point of water is **212°F** (which is equivalent to 100°C).

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#### 35. One horse power is equal to:

1. 75 watt
2. 102 watt
3. 550 watt
4. 746 watt

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**Answer:** **4) 746 watt**

**Explanation:** The mechanical horsepower (hp) is defined as **746 watts**.

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#### 36. The heat treatment process for already hardened steel to soften it is:

1. Full annealing
2. Annealing
3. Normalizing
4. Tempering

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**Answer:** **4) Tempering**

**Explanation:** **Tempering** is the heat treatment process applied to **already hardened** or quenched steel. It involves reheating to a temperature below the lower critical temperature to reduce brittleness, relieve internal stresses, and increase toughness (soften slightly), while retaining most of the hardness.

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#### 37. Conversion of fuel energy directly into mechanical energy is done by:

1. Fuel cell
2. Ni-cd cell
3. Solar cell
4. Electrolytic cell

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**Answer:** **1) Fuel cell**

**Explanation:** While not "directly" into mechanical energy, a **fuel cell** converts the chemical energy of a fuel (like hydrogen) directly into electrical energy, which can then be used to power an electric motor (mechanical energy) with very high efficiency, more directly than heat engines. Among the options, it is the most correct.

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#### 38. Which of the following takes heat energy and converts it into mechanical work in a cycle?

1. Heat pump
2. Heat engine
3. Refrigeration
4. Generator

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**Answer:** **2) Heat engine**

**Explanation:** A **heat engine** operates in a thermodynamic cycle, absorbing heat from a high-temperature source, converting part of it into useful **mechanical work**, and rejecting the remainder to a low-temperature sink.

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#### 39. Degree of freedom for mechanism with 8 links and 9 revolute pairs is:

1. 1
2. 2
3. 3
4. 4

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**Answer:** **3) 3**

**Explanation:** Using Gruebler's equation for planar mechanisms with only revolute pairs (each having 1 degree of freedom, f=1):

Where:

* $$L$$ = number of links = 8
* $$J$$ = number of lower pairs (revolute pairs) = 9

Calculation:

The degree of freedom is **3**.

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#### 40. Which of the risk is associated with software company?

1. Technology risk
2. Organizational risk
3. Environmental risk
4. None

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**Answer:** **1) Technology risk**

**Explanation:** Software companies are particularly exposed to **technology risks**, including rapid obsolescence, software bugs, security vulnerabilities, integration failures, and reliance on specific platforms or languages.

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#### 41. Heat flux is given by:

1. $$q = Q / A$$
2. $$q = A / Q$$
3. $$q = A^{\*}Q$$
4. $$q = A^{\*}Q^{2}$$

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**Answer:** **1)** $$q = Q / A$$

**Explanation:** Heat flux $$(q)$$ is defined as the rate of heat transfer $$(Q)$$ per unit area $$(A)$$ through which the heat flows.

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#### 42. Which of the following is not done by a fuel injector?

1. Control the speed of engine
2. Atomize the fuel
3. Inject the fuel
4. Filter the fuel

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**Answer:** **4) Filter the fuel**

**Explanation:** A fuel injector's primary functions are to **meter, atomize, and inject** fuel into the combustion chamber. **Filtering** the fuel is the job of a separate component, the fuel filter.

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#### 43. The minimum operating pressure for free circulation boiler is:

1. 500 kPa
2. 300 kPa
3. 400 kPa
4. 180 kPa

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**Answer:** **4) 180 kPa**

**Explanation:** Natural (or free) circulation boilers rely on the density difference between hot and cold water to drive flow. A minimum pressure (typically around **180 kPa** or 1.8 bar) is required to prevent steam formation in the downcomers and ensure stable circulation.

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#### 44. Top to down analysis in hazard analysis is:

1. FTA
2. FMEA
3. Fish bone diagram
4. Bath tube diagram

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**Answer:** **1) FTA**

**Explanation:** **Fault Tree Analysis (FTA)** is a **top-down**, deductive failure analysis technique. It starts with a potential undesirable top event (accident) and works downwards to identify all possible causes (basic events) using logic gates.

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#### 45. CNG is a:

1. Liquid fuel
2. Gaseous fuel
3. Solid fuel

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**Answer:** **2) Gaseous fuel**

**Explanation:** CNG stands for **Compressed Natural Gas**, primarily methane, which is stored and used as a **gaseous fuel**.

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#### 46. Which gear is used for intersecting shaft?

1. Bevel gear
2. Spur gear
3. Helical gear
4. Worm gear

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**Answer:** **1) Bevel gear**

**Explanation:** **Bevel gears** are designed to transmit motion between **intersecting shafts**, most commonly at a 90-degree angle.

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#### 47. Which type of cantilever beam provides more economic loading?

1. Rectangular beam
2. I-section beam
3. Circular beam
4. None

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**Answer:** **2) I-section beam**

**Explanation:** For a cantilever beam in bending, an **I-section** is more economical (higher strength-to-weight ratio) because it concentrates most of the material in the flanges, away from the neutral axis, where bending stresses are highest.

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#### 48. How can we join two sheet metals?

1. Bending
2. Seaming
3. Welding
4. Rolling

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**Answer:** **2) Seaming**

**Explanation:** **Seaming** is a specific sheet metal joining process where the edges of two sheets are folded over each other (often locked or crimped) to form a seam. While welding is also common, seaming is a distinct mechanical joining method for sheet metal.

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#### 49. What is called the temperature where the ignition of substance starts?

1. Ignition point
2. Flash point
3. Fire point
4. Boiling point

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**Answer:** **1) Ignition point** (more precisely **Ignition Temperature** or **Autoignition Temperature**)

**Explanation:** The **ignition temperature** (or autoignition temperature) is the minimum temperature at which a substance will spontaneously ignite and sustain combustion **without** an external spark or flame.

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#### 50. Fourier equation is:

1. $$Q^{\prime} = -k\Delta x / dt$$
2. $$Q^{\prime} = -k\Delta t / dx$$
3. $$Q^{\prime} = -k\Delta x^{2} / dt$$
4. $$Q^{\prime} = -kax$$

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**Answer:** **(Correct form:** $$q = -k \frac{dT}{dx}$$**) Closest is option 2.**

**Explanation:** Fourier's Law of Heat Conduction states that the heat flux $$(q)$$ is proportional to the negative temperature gradient.

Where $$q$$ is heat flux, $$k$$ is thermal conductivity, and $$\frac{dT}{dx}$$ is the temperature gradient. Option 2 approximates this as $$-k \Delta t / dx$$.

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#### 51. What is the centroid of the given hatched region from base?

*(Diagram missing - Assumption: A common problem is a composite shape, e.g., a rectangle with a semicircle on top)*

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**Answer:** **\[Cannot be calculated without the diagram. For a rectangle of height h and width b surmounted by a semicircle of radius r=b/2, the centroid from the base would be calculated using the composite area method].**

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#### 52. Determine the specific speed of the turbine with power 30000 kW, head of 35 m and rotating speed of 15 rpm.

1. 10
2. 30
3. 100
4. 300

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**Answer:** **2) 30 (approximately)**

**Explanation:** Specific speed (metric, for turbines) is given by:

Where:

* $$N$$ = speed in rpm = 15
* $$P$$ = power in kW = 30000
* $$H$$ = head in m = 35

Calculate:

The specific speed is approximately **30**.

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#### 53. Determine the cutting speed of the grinder with diameter 15 mm and rpm of 150.

1. 7.07 m/s
2. 0.118 m/s
3. 70.7 m/min
4. 11.8 m/min

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**Answer:** **2) 0.118 m/s** (and **3) 70.7 m/min** is also correct but in different units)

**Explanation:** Cutting speed (surface speed) $$V$$ is given by:

Where $$D$$ is diameter in meters, and $$N$$ is rotational speed in revolutions per second (rps).

* $$D = 15 \text{ mm} = 0.015 \text{ m}$$
* $$N = 150 \text{ rpm} = 150/60 = 2.5 \text{ rps}$$

In m/s

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#### 54. Determine the maximum temperature in the diesel cycle with initial p=10 bar, T=295 K, compression ratio=4, cut-off ratio=2.

1. 500 K
2. 750 K
3. 1027 K
4. 1200 K

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**Answer:** **3) 1027 K**

**Explanation:** For an ideal Diesel cycle:

* Process 1-2: Isentropic compression.

With $$r = 4$$, $$\gamma = 1.4$$, $$T\_1 = 295 \text{ K}$$.

* Process 2-3: Constant pressure heat addition (cut-off).

Since $$P$$ is constant, $$\frac{T\_3}{T\_2} = \frac{V\_3}{V\_2} = \beta$$.

The maximum temperature $$(T\_3)$$ is approximately **1027 K**.

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#### 55. A solid with 3.5 m width and 1 m depth is floating in water. Density = 850 kg/m³, length=5 m. Find centre of buoyancy from surface.

1. 0.85
2. 0.95
3. 1.65
4. 1.15

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**Answer:** **1) 0.85** (This is the draft depth, likely what the question asks for)

**Explanation:** For a floating body, the draft $$(h)$$ is found from equilibrium: Weight of body = Weight of displaced water. Let the draft be $$h$$.

Mass terms cancel width, length, giving:

The **centre of buoyancy** is at the centroid of the submerged volume. For a rectangular cross-section, this is at $$h/2 = 0.425 \text{ m}$$ from the bottom. However, the question asks "from surface", which would be $$1 - 0.425 = 0.575 \text{ m}$$. Since this doesn't match, the question likely asks for the **draft** itself: **0.85 m**.

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#### 56. The condition for self-locking in a brake is:

1. $$a > \mu c$$
2. $$a = \mu c$$
3. $$a < \mu c$$
4. $$a = 0$$

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**Answer:** **3)** $$a < \mu c$$

**Explanation:** For a simple band/drum brake, self-locking occurs when the friction force alone is sufficient to hold the load without any application force. The condition for self-locking is that the moment arm of the actuating force $$(a)$$ is less than the product of the coefficient of friction $$(\mu)$$ and the drum radius $$(c)$$, i.e., $$a < \mu c$$.

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#### 57. Which type of projection is it when the projecting lines are parallel to each other & perpendicular to projecting plane?

1. Parallel projection
2. Orthographic projection
3. Isometric projection
4. Perspective projection

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**Answer:** **2) Orthographic projection**

**Explanation:** **Orthographic projection** is a specific type of parallel projection where the projectors (lines of sight) are parallel to each other and **perpendicular** to the plane of projection.

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#### 58. How does hypereutectoid steel form?

1. $$L \to \gamma + Fe\_3C$$
2. $$\gamma \to \alpha + Fe\_3C$$
3. $$L + \delta \to \gamma$$
4. $$L \to \gamma$$

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**Answer:** **2)** $$\gamma \to \alpha + Fe\_3C$$

**Explanation:** Hypereutectoid steel has a carbon content above 0.8% (eutectoid point). Upon cooling from the austenite ($$\gamma$$) phase field, it first precipitates **proeutectoid cementite (Fe₃C)** along the grain boundaries. Upon reaching the eutectoid temperature, the remaining austenite transforms into pearlite ($$\alpha + Fe\_3C$$). The overall transformation is from austenite to ferrite and cementite.

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#### 59. Calculate the work done in the following process: $$P\_a = 200, P\_b = 800, V\_a = 0.1, V\_b = 0.5$$

1. 200 J
2. 120 J
3. 80 J
4. 160 J

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**Answer:** **Assuming linear P-V process and units of kPa and m³, the work is 200 kJ. Closest relevant option is 1) 200 J (likely a unit inconsistency).**

**Explanation:** Work done for a process on a P-V diagram is the area under the curve. For a **straight-line process** from state a to state b, work is the area of a trapezoid.

If pressure is in **kPa** and volume in **m³**, work is in **kJ**: $$W = 200 \text{ kJ}$$. If the units were intended as Pa and m³, work would be 200,000 J. Given the options, the intended answer is likely **200**.

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#### 60. Which type of projection is it when the projecting lines are parallel to each other & perpendicular to projecting plane?

1. Parallel projection
2. Orthographic projection
3. Isometric projection
4. Perspective projection

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**Answer:** **2) Orthographic projection**

**Explanation:** **Orthographic projection** is a specific type of parallel projection where the projectors (lines of sight) are parallel to each other and **perpendicular** to the plane of projection.

</details>

***

***

## Long Questions 40 marks

#### 61. The ratio of maximum to mean velocity of laminar fluid passing through two parallel plates is:

1. 1.0
2. 1.5
3. 2.0
4. 3.0

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**Answer:** **2) 1.5**

**Explanation:** For fully developed, laminar flow between two infinite parallel plates (plane Poiseuille flow), the velocity profile is parabolic.

* Maximum velocity ($$u\_{max}$$) occurs at the centerline.
* The ratio of maximum velocity to mean velocity ($$u\_{mean}$$) is constant:

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#### 62. The process of extraction of (type of) iron is:

1. Smelting
2. Roasting
3. Calcination
4. Leaching

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**Answer:** **1) Smelting**

**Explanation:** The primary industrial process for extracting iron from its ore (hematite, magnetite) is **smelting** in a **blast furnace**. The process involves reduction of iron oxides using coke (carbon) at high temperatures.

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#### 63. Free convection depends on which of the following dimensionless numbers?

1. Reynolds Number
2. Grashof Number
3. Mach Number
4. Weber Number

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**Answer:** **2) Grashof Number**

**Explanation:** **Free (or natural) convection** is driven by buoyancy forces due to density variations caused by temperature gradients. The **Grashof number (Gr)** represents the ratio of buoyancy to viscous forces and is the key dimensionless parameter characterizing free convection flow.

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#### 64. Calculate the enthalpy of 1 kg of steam when, efficiency of boiler is 80%, feed water temperature is 50°C, and steam is dry saturated at 10 bar.

1. 2500 kJ/kg
2. 2650 kJ/kg
3. 2778 kJ/kg
4. 3000 kJ/kg

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**Answer:** **3) 2778 kJ/kg (This is the enthalpy of the steam, boiler efficiency is extra information)**

**Explanation:** From steam tables at 10 bar (1 MPa), for **dry saturated steam**:

* Enthalpy of saturated water ($$h\_f$$) ≈ 762.8 kJ/kg
* Enthalpy of vaporization ($$h\_{fg}$$) ≈ 2015.3 kJ/kg
* Enthalpy of dry saturated steam ($$h\_g$$):

The boiler efficiency (80%) and feed water temperature (50°C, $$h\_{fw} \approx 209.3 \text{ kJ/kg}$$) would be used to calculate the **heat supplied**, not the enthalpy of the steam produced.

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#### 65. Welding heat is inversely proportional to:

1. Voltage
2. Current
3. Travel Speed
4. Electrode Diameter

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**Answer:** **3) Travel Speed**

**Explanation:** The heat input per unit length in arc welding is given by:

Where $$V$$ is voltage, $$I$$ is current, and $$S$$ is travel speed (mm/min). Therefore, for a given voltage and current, the heat input $$H$$ is **inversely proportional to the travel speed** $$S$$.

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#### 66. Corrosion depends on:

1. Material Composition Only
2. Environment Only
3. Both Material and Environment
4. None of the above

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**Answer:** **3) Both Material and Environment**

**Explanation:** Corrosion is an electrochemical process that depends on:

* **Material factors:** Chemical composition, microstructure, presence of stresses, surface condition.
* **Environmental factors:** Presence of an electrolyte, temperature, pH, oxygen concentration, presence of aggressive ions (e.g., chlorides).

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#### 67. Which of the following exhaust content cannot be measured in emission tests?

1. CO
2. CO₂
3. H₂O
4. NOx

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**Answer:** **3) H₂O**

**Explanation:** Standard automotive emission tests typically measure pollutants like **Carbon Monoxide (CO)**, **Carbon Dioxide (CO₂)**, **Hydrocarbons (HC)**, and **Nitrogen Oxides (NOx)**. Water vapor (H₂O) is a major product of combustion but is not considered a pollutant and is usually not measured in standard regulatory tests.

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#### 68. If a prismatic force P is applied on a solid cylinder of cross sectional area A, then which expression is correct?

1. $$\sigma = P \times A$$
2. $$\epsilon = P / (A E)$$
3. $$\sigma = P / A$$
4. $$\delta = P \times L$$

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**Answer:** **3)** $$\sigma = P / A$$

**Explanation:** For a prismatic bar (constant cross-section) under axial load, the engineering **stress (σ)** is defined as the applied force (P) divided by the original cross-sectional area (A).

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#### 69. Expansion process in Rankine cycle is:

1. Adiabatic
2. Isochoric
3. Isothermal
4. Polytropic

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**Answer:** **1) Adiabatic**

**Explanation:** In the ideal Rankine cycle, the expansion of steam in the turbine is modeled as an **adiabatic and reversible** process, i.e., **isentropic**.

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#### 70. Value of polytropic index for adiabatic process in an ideal gas is:

1. n = 0
2. n = 1
3. n = k (Cp/Cv)
4. n = ∞

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**Answer:** **3) n = k (Cp/Cv)**

**Explanation:** For an **adiabatic** and **reversible** process (i.e., isentropic) of an ideal gas, the polytropic index $$n$$ is equal to the ratio of specific heats, $$k$$ or $$\gamma = C\_p / C\_v$$. The process follows $$P V^{\gamma} = \text{constant}$$.

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#### 71. Thermal stress on a material depends on:

1. Young's Modulus Only
2. Coefficient of Thermal Expansion Only
3. Temperature Change Only
4. Young's Modulus, Coefficient of Expansion, and Temperature Change

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**Answer:** **4) Young's Modulus, Coefficient of Expansion, and Temperature Change**

**Explanation:** For a fully constrained body subjected to a uniform temperature change ($$\Delta T$$), the induced thermal stress ($$\sigma\_{th}$$) is given by:

Where:

* $$E$$ = Young's Modulus
* $$\alpha$$ = Coefficient of Linear Thermal Expansion
* $$\Delta T$$ = Temperature Change It depends on all three factors.

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#### 72. Which one of the following is not the standard attachment for milling operation?

1. Arbor
2. Collet
3. Face mill holder
4. Three-jaw chuck

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**Answer:** **4) Three-jaw chuck**

**Explanation:** A **three-jaw chuck** is a standard workholding device for **lathes**. Standard milling machine attachments and tool holders include arbors (for mounting saws or slab mills), collets (for end mills), and face mill holders.

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#### 73. Calculate the present value of the future worth of Rs 500 at interest rate 8% PA and time 5 years.

1. Rs 340
2. Rs 360
3. Rs 380
4. Rs 400

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**Answer:** **1) Rs 340 (approximately)**

**Explanation:** Present Value (PV) is calculated as:

Where:

* $$FV$$ = Future Value = 500
* $$i$$ = interest rate = 8% = 0.08
* $$n$$ = number of periods = 5 years

Present Value ≈ **Rs 340**.

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#### 74. Which one gives return on investment to the investors?

1. MARR
2. IRR
3. ERR
4. Payback Period

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**Answer:** **2) IRR**

**Explanation:** The **Internal Rate of Return (IRR)** is the discount rate that makes the net present value (NPV) of a project zero. It represents the **projected annual rate of growth/return** an investment is expected to generate, making it a direct measure of return on investment for investors.

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#### 75. If viscous force is dominating inertia force in a fluid flow, the fluid flow is:

1. Laminar
2. Turbulent
3. Transitional
4. Compressible

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**Answer:** **1) Laminar**

**Explanation:** The Reynolds number (Re) represents the ratio of inertial forces to viscous forces.

* Low Re (Re < 2000 for pipe flow) → **Viscous forces dominate** → Flow is smooth, orderly, and **laminar**.
* High Re → Inertial forces dominate → Flow is chaotic and **turbulent**.

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#### 76. The type of maintenance in which production is not halted is:

1. Predictive maintenance
2. Breakdown maintenance
3. Scheduled maintenance
4. Preventive maintenance

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**Answer:** **1) Predictive maintenance**

**Explanation:** **Predictive maintenance** uses real-time monitoring (vibration, temperature, oil analysis) to predict failures before they occur. Maintenance is performed only when needed, ideally **without halting production** for unnecessary scheduled checks. Scheduled and preventive maintenance often require planned downtime.

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#### 77. The smell of exhaust in diesel engine is due to presence of:

1. Hydrocarbon
2. Methane
3. Nitrogen
4. Ethane

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**Answer:** **1) Hydrocarbon**

**Explanation:** The characteristic smell of diesel exhaust is primarily due to **unburnt or partially burnt hydrocarbons (HC)** and other organic compounds. While methane and ethane are hydrocarbons, the term "Hydrocarbon" encompasses the broader range of compounds responsible.

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#### 78. The manufacturing process for production of hollow samples/pipe is called:

1. Extrusion
2. Drawing
3. Casting
4. Forging

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**Answer:** **1) Extrusion**

**Explanation:** **Extrusion** is a process where a material is forced through a die to create long products of a fixed cross-sectional profile. It is the primary method for producing **hollow sections** like pipes and tubes from materials like aluminum and plastics.

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#### 79. By considering following activities of a project, the project duration will be:

\[Table: A(4), B(5), C(3), D(7), E(5) days, predecessors: A:-, B:-, C:-, D:C, E:A,B,D]

<figure><img src="https://1335304073-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F6BUDIDLBlnJ37FLFExZ6%2Fuploads%2FVgNdNIoj6Sy8GVjkOPj4%2Fimage.png?alt=media&#x26;token=766f5ee6-147d-4cf0-b5ed-33b08a0487f3" alt=""><figcaption></figcaption></figure>

1. 9 days
2. 10 days
3. 15 days
4. 24 days

***

#### 80. Under how many categories does the Nepal Engineering Council issue licenses?

1. 2
2. 3
3. 4
4. 5

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**Answer:** **2) 3**

**Explanation:** As per the Nepal Engineering Council Act and regulations, the Council issues licenses in **three** main categories:

1. Professional Engineer
2. Engineering Consultant
3. Engineering Firm

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