Fitter MCQ Quiz - Objective Question with Answer for Fitter - Download Free PDF

Explanation:

Hammers:

• An engineer's hammer is a hand tool used for striking purposes while punching, bending, straightening, chipping, forging, or riveting.
• The hammer is made of drop-forged carbon steel, while the wooden handle must be capable of absorbing shock.

Specification:

• An engineer's hammers are specified by their weight and the shape of the pein.
• Their weight varies from 125 grams to 750 grams.
• The weight of an engineer's hammer, used for marking purposes, is 250 grams.

Major parts of a hammer:

Face:

• The face is the striking portion. A slight convexity is given to it to avoid digging off the edge. It is used for striking while chipping, bending, punching, etc.

Pein:

• The pein is the other end of the head. It is used for shaping and forming work like riveting and bending.

Cheek:

• The cheek is the middle portion of the hammer-head. The weight of the hammer is stamped here. This portion of the hammer-head is left soft.

Eyehole:

• The eyehole is meant for fixing the handle. It is shaped to fit the handle rigidly. The wedges fix the handle in the eyehole.

Explanation:

• A fire extinguisher, flame extinguisher or simply extinguisher is an active fire protection device used to extinguish or control small fires, often in emergency situations.
• It is not intended for use on and out off control fire. 
• Many types of fire extinguishers are available with different extinguishing 'agents' to deal with different classes of fires. 

Carbon dioxide (CO2):

• This type is easily distinguished by the distinctively shaped discharge horn.
• Suitable for class B fires
• Best suited where contamination by deposits must be avoided.
• Not generally effective in the open air.
• If the nozzle gets extremely cold, then it is dangerous to use that Extinguisher.
• CO2 extinguishers have Black labels on the top of the cylinder

Water-filled extinguishers 

• There are two methods of operation.
  1. Gas cartridge type
  2. Stored pressure type
• Water-filled extinguishers have Red labels on the top of the cylinder

Foam extinguishers:

• These may be of stored pressure or gas cartridge types.
• Foam extinguishers are most suitable for:
  1. flammable liquid fires
  2. running liquid fires
• Must not be used where electrical equipment is involved.
• Foam extinguishers have Cream labels on the top of the cylinder

Dry powder extinguishers:

• Extinguishers fitted with dry powder may be of the gas cartridge or stored pressure type.
• The main distinguishing feature is the fork-shaped nozzle.
• Powders have been developed to deal with class D fires. 
• Dry powder extinguishers have Blue labels on the top of the cylinder

Halon extinguishers:

• These extinguishers may be filled with carbon tetrachloride (CTC) and bromochlorodifluoro methane (BCF).
• They may be of the either gas cartridge or stored pressure type.
• They are more effective in extinguishing small fires involving pouring liquids.
• These extinguishers are particularly suitable and safe to use on electrical equipment as the chemicals are electrically non-conductive.

Explanation:

Class D Fires

• Class D fires involve combustible metals. These types of fires are particularly dangerous and challenging to extinguish due to the chemical properties and high burning temperatures of the metals involved. Common metals that fall under this category include aluminum, magnesium, titanium, and zirconium.

Characteristics of Combustible Metals:

• High Burning Temperatures: Combustible metals burn at extremely high temperatures, which can exceed 5,000 degrees Fahrenheit. This makes them difficult to extinguish with water or standard fire extinguishers.
• Reactivity with Water: Many combustible metals react violently with water, producing flammable hydrogen gas and potentially causing explosions. Therefore, using water to extinguish a Class D fire can exacerbate the situation.
• Specialized Extinguishing Agents: Class D fires require specific extinguishing agents, such as dry powders designed to absorb heat and smother the fire. These agents are formulated to prevent the metal from reacting with oxygen and spreading the fire.

Common Combustible Metals:

• Aluminum: Commonly used in manufacturing and construction, aluminum can ignite when subjected to high temperatures or friction. Once ignited, it burns intensely and can be difficult to control.
• Magnesium: Found in automotive parts, aircraft, and some consumer products, magnesium burns with a bright white flame and reacts violently with water.
• Titanium: Used in aerospace and medical applications, titanium burns at high temperatures and is challenging to extinguish using conventional methods.
• Zirconium: Found in some industrial processes and specialized equipment, zirconium is highly flammable and requires careful handling to prevent fires.

Explanation:

Back-off Angle in Broaching Tools

• The back-off angle in a broaching tool is a critical feature that ensures smooth operation and prevents the tool from rubbing against the workpiece. This angle is provided on the cutting teeth of the broaching tool to ensure that only the cutting edges make contact with the material being machined. By avoiding unnecessary contact between the tool and the workpiece, the back-off angle minimizes friction and heat generation, leading to improved tool life and better surface finish of the workpiece.

Function of the Back-off Angle:

• The back-off angle is essentially a relief angle that ensures the clearance between the tool and the workpiece. When the tool moves through the material, this angle ensures that only the cutting edge interacts with the workpiece, while the rest of the tool remains clear. This design prevents rubbing or dragging of the tool's body against the workpiece, which could otherwise lead to wear, damage, and poor machining results.
• The back-off angle is particularly important in broaching operations, as broaching tools typically have multiple cutting teeth arranged in a series. Each tooth removes a small amount of material, progressively shaping the workpiece to the desired dimensions. Without an appropriate back-off angle, the subsequent teeth might rub against the material, causing heat buildup, tool wear, and potential damage to the workpiece.

Advantages of the Back-off Angle:

• Prevents rubbing and excessive friction between the tool and the workpiece.
• Reduces heat generation during the machining process.
• Improves tool life by minimizing wear.
• Enhances the surface finish of the machined part.
• Ensures efficient and smooth material removal by each cutting tooth.

Explanation:

Parkerizing

• Parkerizing, also known as phosphate coating, is a chemical process used to apply a protective layer of phosphate to ferrous metals (such as steel and iron). This process enhances the corrosion resistance of the surface and provides a base for paint or other coatings to adhere better. In the context of the statement provided, if a part is immersed in a heated magnesium dihydrogen phosphate solution, it undergoes the Parkerizing process. This solution is used to create a uniform, durable phosphate coating on the surface of the metal. The process is commonly employed in industries like automotive, firearms, and military equipment manufacturing.

How Parkerizing Works:

Parkerizing involves immersing the metal part in a heated phosphate-based solution, typically containing zinc, manganese, or magnesium phosphates. The process proceeds as follows:

• Preparation: The metal surface is thoroughly cleaned to remove dirt, oil, and existing rust. This is often done using degreasing agents or abrasive methods like sandblasting.
• Immersion: The cleaned metal part is immersed in the heated phosphate solution. The temperature of the solution is typically maintained between 88°C to 99°C (190°F to 210°F).
• Chemical Reaction: The solution reacts with the metal surface, forming an insoluble phosphate layer. This layer acts as a protective barrier and improves corrosion resistance.
• Post-Treatment: After the coating forms, the part is rinsed to remove any residual solution. It may also be treated with oil or other sealants to enhance its protective properties further.

Applications of Parkerizing:

• Military Equipment: Parkerizing is widely used in the production of firearms and other military-grade components to improve durability and resistance to harsh environments.
• Automotive Industry: The process is applied to engine parts, chassis components, and other metal parts to prevent corrosion and improve paint adhesion.
• Tool Manufacturing: Tools and hardware undergo Parkerizing to enhance their lifespan and performance.

GIven:

Length of the cylinder (h) = 1.4 m = 140 cm, External radius of cylinder, R = 9 cm and internal radius of cylinder = r cm

Concept:

Volume of solid cylinder, \(V_s=\pi R^2h\)

Volume of hollow cylinder, \(V_h=\pi (R^2-r^2)h\)

Calculation:

Volume of hollow cylinder = \(V_h= \pi (R^2-r^2)h\)

\(\Rightarrow 7480=\frac{22}{7} \times (9^2-r^2) \times 140\)

\(\Rightarrow(81-r^2) = 17\)

⇒ r = 8 cm

The train crosses = 200 + 400 = 600 m

∴ Speed of the train = 600/40 = 15 m/s = 15 × (18/5) km/hr = 54 km/hr

The correct answer is Cohesive force between molecules.

Key Points

• Surface tension: Surface tension is a measure of the cohesive forces between liquid molecules present at the surface.​
• Molecules at the surface of a liquid are partly exposed to the surrounding. The molecules at the liquid-air interface experience fewer interactions and have more energy to escape to the surrounding.
• Therefore, energy is required to bring molecules from the bulk of the liquid to the surface. The stronger the intermolecular interaction, the greater is the energy required to increase the surface area of a liquid.
• This energy is called the surface energy and is related to surface tension as

• ​Surface tension =\(\frac{ surface \:energy}{area}\)

The correct answer is Sonorous.

Key Points

• A sonorous is a substance which is capable of producing sound. Metals are generally sonorous they produce sound on being struck or hit by something. 
• The physical property of the metal produced a ringing sound when it strikes on a hard surface is called sonority, hence the temple bells or school bells are made up of sonorous metals.

Additional Information

• Ductile is a material that is able to draw out into thin wire and deformed without losing its toughness. 
• Malleable is a material able to be pressed or hammered into shape without cracking or breaking.

⇒ Required sum = 2 + 4 + 6 + 8 + ……. + 36

⇒ Required sum = 2(1 + 2 + 3 + …… + 18)

We know that,

Sum of first n natural numbers = n(n + 1)/2

⇒ Required sum = 2 × n × (n + 1)/2      (where n = 18)

Explanation:

Calculation:

Let an equal number of 1 rupee, 2 rupee, and 5 rupee coins be x

So, (1 × x + 2 × x + 5 × x) = 184

⇒ 8x = 184

⇒ x = 23

The correct answer is blue.

Key Points

• Gold and copper happen to absorb blue and violet light, leaving yellow light in the spectrum.
• So gold and copper are yellowish in colour.
• The only two non-silvery metals in the world are gold and copper.
• A metal is defined as an element that readily forms positive ions (cations) and has metallic bonds.
• These elements have electrons that are loosely held to the atoms, and will readily transfer them. 
• Most metals' electrons reflect all colours equally which are in the visible spectrum of light.
• So those metals appear as white silver.

Explanation:

Explanation:

• A fire extinguisher, flame extinguisher or simply extinguisher is an active fire protection device used to extinguish or control small fires, often in emergency situations.
• It is not intended for use on and out off control fire. 
• Many types of fire extinguishers are available with different extinguishing 'agents' to deal with different classes of fires. 

Carbon dioxide (CO2):

• This type is easily distinguished by the distinctively shaped discharge horn.
• Suitable for class B fires
• Best suited where contamination by deposits must be avoided.
• Not generally effective in the open air.
• If the nozzle gets extremely cold, then it is dangerous to use that Extinguisher.
• CO₂ extinguishers have Black labels on the top of the cylinder

Water-filled extinguishers 

• There are two methods of operation.
  1. Gas cartridge type
  2. Stored pressure type
• Water-filled extinguishers have Red labels on the top of the cylinder

Foam extinguishers:

• These may be of stored pressure or gas cartridge types.
• Foam extinguishers are most suitable for:
  1. flammable liquid fires
  2. running liquid fires
• Must not be used where electrical equipment is involved.
• Foam extinguishers have Cream labels on the top of the cylinder

Dry powder extinguishers:

• Extinguishers fitted with dry powder may be of the gas cartridge or stored pressure type.
• The main distinguishing feature is the fork-shaped nozzle.
• Powders have been developed to deal with class D fires. 
• Dry powder extinguishers have Blue labels on the top of the cylinder

Halon extinguishers:

• These extinguishers may be filled with carbon tetrachloride (CTC) and bromochlorodifluoro methane (BCF).
• They may be of the either gas cartridge or stored pressure type.
• They are more effective in extinguishing small fires involving pouring liquids.
• These extinguishers are particularly suitable and safe to use on electrical equipment as the chemicals are electrically non-conductive.