RCFL MT Mechanical Mock Test - 10 - Mechanical Engineering MCQ

Punching/Blanking: Punching or blanking is a process in which the punch removes a portion of material from the larger piece or a strip of sheet metal. If the small removed piece is discarded, the operation is called punching, whereas if the small removed piece is the useful part and the rest is scrap, the operation is called blanking.

Piercing: It is a process by which a hole is cut (or torn) in metal. It is different from punching in that piercing does not generate a slug.

Perforating: It is an operation in which a number of uniformly spaced holes are punched in a sheet of metal. The holes may be of any size or shape. They usually cover the entire sheet of metal.

Nothing: It is an operation in which a specified small amount of metal is cut from the edges.

Lancing: It is an operation of cutting a sheet metal through a small length and then bending this cut portion.

Impulse Turbine: If the energy available is only kinetic energy at the inlet of the turbine, the turbine is known as an impulse turbine. e.g., a Pelton wheel turbine.

Reaction Turbine: If at the inlet of the turbine, the water possesses kinetic energy and pressure energy, the turbine is known as a reaction turbine. e.g., e Francis and Kaplan turbine.

Tangential flow turbines: In this type of turbine, the water strikes the runner in the direction of the tangent to the wheel. Example: Pelton wheel turbine

Radial flow turbines: In this type of turbine, the water strikes in the radial direction. accordingly, it is further classified as

Inward flow turbine: The flow is inward from periphery to the centre (centripetal type); Example: old Francis turbine

Outward flow turbine: The flow is outward from the centre to periphery (centrifugal type); Example: Fourneyron turbine

Axial flow turbine: The flow of water is in the direction parallel to the axis of the shaft. Example: Kaplan turbine and propeller turbine

∴ Francis turbine is a radial inward flowing reaction turbine.

δF/δx = −w

The slope of bending moment diagram = Shear force at that section

Coefficient of performance of the refrigeration system working on reversed Carnot cycle:

Unit of refrigerating effect = One tonne of refrigeration

1 TR = 3.5 kW

Calculation:

Given: RE = 1 TR = 3.5 kW

W = 700 kJ/ten minutes

COP = 3

Stress-Strain

σ ∝ ϵ

σ = Eϵ

where E is known as Young’s modulus of elasticity.

Since strain (ϵ) is non – dimensional, the unit of E must be the same as those of stress (σ). Thus, E can be expressed in N/mm2, Pa, MPa, GPa, etc.

• Unit of stress: N/mm2 (MPa)

• Unit of strain: Dimensionless

• Unit of Force: N

• Unit of length: mm

δQ = δW + ΔU

Since internal energy is a point function, so for a cyclic process, a change in internal energy, i.e., ΔU, will be zero (because the initial and final state will be the same).

For the cyclic process:

δQ = δW

∮ δQ = ∮ δW

The first law of thermodynamics states that for a cyclic process, the cyclic integral of heat is equal to the cyclic integral of work.

Cementite: Cementite or Iron Carbide has the chemical formula Fe3C and contains 6.67% carbon by weight. It is the hardest structure that appears in the iron-carbon equilibrium diagram. Cementite has an orthorhombic crystal structure and is extremely hard and brittle as compared to austenite and ferrite.

Martensite: It is a metastable phase of steel formed by the transformation of austenite below 320°C. Martensite is an interstitial supersaturated solid carbon solution in α – Iron and has a body-centred tetragonal lattice. It has a carbon content of up to 2% and is extremely hard and brittle. It is a product of rapid cooling (quenching) and possesses an acicular or needle-like structure.

The hardness of steel depends upon the amount of cementite. Martensite was obtained after hardening treatment of steel.

Steels with low carbon content do not respond appreciably to hardening treatment because the main constituent is soft ferrite. If hypo-eutectoid steel is cooled rapidly, martensite is formed.

Introduction of TIG Welding

Gas Tungsten Arc Welding (GTAW), also known as tungsten inert gas (TIG) welding, is a process that produces an electric arc maintained between a non-consumable tungsten electrode and the part to be welded.

Inert Gas in TIG Welding

The heat-affected zone, the molten metal, and the tungsten electrode are all shielded from atmospheric contamination by a blanket of inert gas fed through the GTAW torch.

Inert gas is inactive or deficient inactive chemical properties. The shielding gas serves to blanket the weld and excludes the active properties in the surrounding air. Inert gases, such as Argon and Helium, do not chemically react or combine with other gases.

Fuel gas analysis refers to the determination of the composition of exhaust gases. It can be done theoretically and experimentally.

Various devices available for measuring the composition of products of combustion (flue gas) are Orsat Analyzer, Gas chromatograph, Infrared analyzer, and Flame ionization detector, etc.

Orsat Apparatus: It is used for carrying out volumetric analysis of dry products of combustion.

Bomb Calorimeter: It is used to determine the higher calorific value of solid and liquid fuels.

Barometer: A barometer is used to measure local atmospheric pressure.

Rope dynamometer: A rope brake dynamometer is used to test the power of engines.

As the hot coffee remains hot for a long time so neither heat nor mass is exchanged with the surroundings and hence it is an example of isolated system.

The original sentence "Darjeeling grows tea" is in the active voice.

The correct option that expresses the same sentence in the passive voice is:

D. Tea is grown in Darjeeling.

The segment is in passive voice, thus only a verb in third form is eligible for the blank. Among all the given options, only ‘discovered’ fits the blank as the virus already existed in the monkeys but was found in 1970.

Hence, option D is correct.

Pediatrician: A doctor who treats children

• Meaning of Hesitated: Pause in indecision before saying or doing something.
• Meaning of Stopped: (of an event, action, or process) come to an end; cease to happen.
• Meaning of Paused: interrupt action or speech briefly
• Meaning of Slowed: reduce one's speed or the speed of a vehicle or process
• Meaning of Postponed: cause or arrange for (something) to take place at a time later than that first scheduled

The correct order will be:
Then → it struck me (P)→ how eminently (S)→ suitable it was(R) → of course.(Q)

When the denominator of an expression contains a term with a square root, the process of converting it to an equivalent expression whose denominator is a rational number is called rationalising the denominator.
By multiplying we will get same expression since 
Therefore, 

Using Rule 1 :
1st number × 2nd number = L.C. M. × H.C.F,
Required number

Height of an equilateral triangle

Hence, Option A is correct.

Let AB be the kite and AC be the level ground
So that BC - AC.
At that point, ∠BAC = 60°and BC = 75m. Let AB = x meters.
Presently AB/BC = coses60° = 2/ √3
=> x/75 = 2/√3 => x = 150/√3 = 150 * √3/3 = 50 √3m.
∴ Length of the string = 50 √3m.

- Volume Formula: Volume = Length × Breadth × Height
- Given Dimensions:
- Length = 8 cm
- Breadth = 6 cm
- Height = 3.5 cm
- Substituting the given values:
- 8 × 6 × 3.5
- 48 × 3.5 = 168
- Result: The volume of the cuboid is 168 cm³.

The below figure shown the total no. of triangles is 8 + 8 + 2 + 6 + 4 = 28

1st term = 0.5
2nd term = 0.5 + 0.05 = 0.55
3rd term = 0.55 + 0.1 = 0.65
4th term = 0.65 + 0.15 = 0.8

Thus, missing number is 5th term = 0.8 + 0.2 = 1

Carpenter, Plumber, Electrician and Blacksmith are in same working category.

The logic follows here is:

It is given that Rahul has 48% marks in 10th, an age of 28 years, and work experience of 5 years.

It is clearly mentioned in the criteria that 10^th marks should be greater than 50% for job P and greater than 60% for job Q. Rahul got 48% marks in 10^th.

Therefore, Rahul, neither qualifies for job P nor for job Q.

Hence, the correct answer is "Neither P nor Q".

The Haryana Assembly passed a bill aimed at curbing illegal immigration, addressing concerns regarding the activities of unregistered travel agents. This legislative action reflects the state's efforts to tackle issues related to immigration and safeguard the interests of its residents.

The Security Council is the primary authority for maintaining international peace and security within the UN.