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:

Alloy:

• An alloy is a substance formed from the combination of two or more metals.
• Alloys can also be formed from combinations of metals and other elements.
• In simpler words, an alloy can be defined as a homogeneous mixture of two or more metals or a metal and a non-metal.
• Brass is an alloy of copper and zinc. The percentage of copper (Cu) and zinc (Zn) is (Cu = 60-80% Zn = 40-20%).
• German silver is a term for various Copper, Zinc, and Nickel alloys, often even containing Lead and Tin.
• German silver is also known as Nickel silver and has the main component Copper with varying quantities of Nickel and Zinc.
• German silver is widely used because of its hardness, toughness, and resistance to corrosion.
• Bronze is an alloy of copper, zinc, and tin.
• Solder is an alloy of lead and zinc.
• Gunmetal is composed of 88 percent copper, 10 percent tin, and 2 percent zinc and is used for gears and bearings that are to be subjected to heavy loads and low speeds.

Explanation:

High-Speed Steel:

• It is an alloy tool steel that retains much of its hardness and toughness at red heat after heat treatment, allowing tools made of it to cut at high speeds even while red-hot through friction.
• High-speed steels (HSS ) get their name from the fact that they may be operated as cutting tools at much higher cutting speeds than is possible with plain carbon tool steels.
• High-speed steels operate at cutting speeds 2 to 3 times higher than carbon steels.
• A common type of high-speed steel contains 18% tungsten, 4% chromium, 1% vanadium, and only 0.5–0.8% carbon.

Types of High-Speed Steel:

18-4-1 High-Speed Steel:

• This steel, containing 18 percent tungsten, 4 percent chromium, and 1 percent vanadium with about 0.75 percent carbon is considered to be one of the best all-purpose tool steels.
• This steel is extensively used for lathe, planer, and shaper tools, drills, and milling cutters.

Cobalt High-Speed Steel:

• This is known as super high-speed steel.
• Normally cobalt is added from 5 to 8 percent to increase better hot hardness and wear resistance than the 18 : 4: 1 type.
• One analysis of cobalt high-speed steel contains 20 percent tungsten, 4 percent chromium, 2 percent vanadium, and 12 percent cobalt.
• The addition of cobalt increases heat resistance and can give a Rockwell hardness of up to 70 Min.

Vanadium High-Speed Steel:

• This steel contains 0.70 percent carbon and more than 1 percent vanadium.
• High vanadium with carbon high-speed steel is superior to the 18:4:1 type for difficult-to-machine materials.
• This has excellent abrasive resistance.

Molybdenum High-Speed Steel:

• This steel containing 6 percent molybdenum, 6 perc tungsten, 4 percent chromium, and 2 percent vanadium has excellent toughness and cutting ability.
• Combining molybdenum, tungsten, and chromium steel creates several alloys commonly called “HSS“, measuring 63–65 Rockwell “C” hardness.

Explanation:

Cast iron:

• Cast iron is a high-carbon alloy of iron with carbon. It usually contains alloy additives such as silicon, manganese, phosphorus, or sulfur also.
• Cast iron contains from 2.06 to 6.67% carbon in the form of cementite or graphite.
• The occurrence of a particular phase of carbon depends on the cooling rate and chemical composition of the alloy.
• One of the types of cast iron is gray cast iron wherein the carbon is present as graphite.
• It is regarded as cast iron of higher quality and is more ductile, easily treatable, has good fluidity, and has a smaller shrinkage casting (around 1.0%) than white cast iron.
• It is used to make bodies, housings, blocks of pumps, compressors, and motors although it is more brittle and susceptible to cracking than steel.
• Grey cast iron is used because of having exceptional damping Capacity (the relative ability of a material to absorb shock or vibration).
• Grey cast iron possesses this property due to the presence of carbon in the form of graphite flakes in the pearlite/ferrite matrix.
• The morphology of graphite as a flake in grey cast iron enables it to absorb both compressive and vibrational loads without initiating a crack.
• In general, vibration can be critical in machinery and can cause an unsatisfactory operation or even failure.

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.

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.