Basic Science and Engineering MCQ Quiz - Objective Question with Answer for Basic Science and Engineering - Download Free PDF

Explanation:

Dimensions in "mm" for different sizes of drawing sheets are as follows:

Explanation:

Projection Systems:

1. First angle projection system  2. Third angle projection system

• Both third angle and first-angle projection display the standard three orthographic views of a part or assembly.

• The key difference between third angle and first angle is the layout of the part on the sheet.

​1. First angle projection system:​

• In first angle projection, top view is located below the front view.

​2.  Third angle projection system:

• In Third angle projection top view is located above the front view.

Additional Information

Orthographic Projection:

Orthographic Projections is a technical drawing in which different views of an object are projected on different reference planes observing perpendicular to respective reference plane.

• Horizontal Plane (HP)
• Vertical Plane (VP)

• Side or Profile Plane (PP)

• Front View (FV) – Projected on VP
• Top View (TV) – Projected on HP
• Side View (SV) – Projected on PP
   

Explanation:

As per IS 9609 (Part 0): 2001, Clause 3.3

Lettering:

• Procedure of writing graphic characters taken from a graphic character set on a (technical) drawing carrier (in addition to the graphical representation).
• The whole of the non-graphical information on a (technical) drawing carrier (text, instructions, dimensions, etc.).
• The whole of the graphic characters of a graphic character set which can be used for transferring non-graphical information onto a (technical) drawing carrier.

Dimensioning of lettering type 'A':

In lettering A type the height of the capital letter is divided into 14 parts.

Important Points

• In lettering B type the height of the capital letter is divided into 10 parts.
• According to the Bureau of Indian Standards the range of nominal size of letters has been specified as follows: 1.8 m, 2.5 mm, 3.5 mm, 5 mm, 7 mm, 10 mm, 14 mm and 20 mm.
• Space between the lines is 3/10 h (height of capital letters).
• Space between the words may be equal to the width of the alphabet M or 3/5 h (height of capital letters).
• Drawing title is written in 7 mm size.
• Drawing numbers, title block, and letters denoting the cutting planes and sections are written in 10 mm size.

Explanation:

A Plan Drawing is a horizontal view of a building or structure, cut at a height of about 1.2 meters (4 feet) above the floor level.

It shows the layout of:

• Walls, Doors, and Windows: Placement and measurements.

• Furniture Layout: Beds, tables, chairs, and other furnishings.

• Electrical Points: Locations for outlets, switches, and lighting fixtures.

• Plumbing Lines: Water supply and drainage systems.

• HVAC Ducts: Air conditioning vents and heating systems.

Types of Plans:

• Floor Plans: General layout of each floor.

• Furniture Plans: Specific layout of furniture arrangements.

• Reflected Ceiling Plans (RCP): Positioning of lights and HVAC on ceilings.

Purpose:

• To visualize how spaces are organized internally.

• To guide builders and electricians during installation.

Explanation:

A Horizon Line is an important element in perspective drawings, representing the observer's eye level.

It is the point where:

• The ground plane and the sky appear to meet in the distance.

• All horizontal parallel lines converge towards vanishing points.

Types of Perspective Drawings:

• One-Point Perspective: A single vanishing point; often used for interiors.

• Two-Point Perspective: Two vanishing points; commonly used for building exteriors.

• Three-Point Perspective: Adds a third vanishing point for height representation.

Purpose of the Horizon Line:

• It acts as a reference for the height of objects in the drawing.

• It guides the placement of buildings, roads, and infrastructure in realistic perspective.

Given

Distance1 = 15 km, Speed1 = 30 km/h

Distance2 = 25 km, Speed2 = 10 km/h

Formula Used:

Speed = Distance/Time

Average speed = Total distance/Total time

Calculation:

According to the question,

Total distance = 15 + 25 = 40 km

Total time = 15/30 + 25/10

⇒ (15 + 75)/30 = 90/30 = 3 hours

Average speed = 40/3 km/h

∴ The average speed for the entire journey is 40/3 km/h.

Given 

D₁ = 15 km, S₁ = 30 km/h

D₂ = 25 km, S₂ = 10 km/h

Formula Used:

Average speed = \(\frac{{{D_1} + {D_2}}}{{\frac{{{D_1}}}{{{S_1}}} + \frac{{{D_2}}}{{{S_2}}}}}\)

Calculation:

Average speed for the entire journey = \(\frac{{15 + 25}}{{\frac{{15}}{{30}} + \frac{{25}}{{10}}}}\)

\(= \frac{{40}}{{0.5 + 2.5}}\)

The correct answer is the Basic input/output system.

Important Points

• It is the program a personal computer's microprocessor uses to get the computer system started after you turn it on.

Explanation:

• A lever is a simple machine consisting of a beam or rigid rod pivoted at a fixed hinge, or fulcrum, used to transfer a force to a load and usually to provide a mechanical advantage.
• On the basis of the locations of fulcrum, load, and effort, the lever is divided into three types.
• First Class Lever:In a first-class lever, the fulcrum is located between the effort and the load. When force is applied to one end of the lever (effort arm), it causes the other end to move, exerting force on the load. Examples include seesaws, crowbars, and scissors.

​

• Second-class lever: In a second-class lever, the load is located between the fulcrum and the effort. This means that the effort arm is always longer than the load arm. When force is applied to the effort arm, it causes the load to move. Examples include wheelbarrows, bottle openers, and nutcrackers.

​

• Third-class lever: In a third-class lever, the effort is applied between the fulcrum and the load. This means that the load arm is always longer than the effort arm. While third-class levers don't provide a mechanical advantage like first and second-class levers, they allow for greater speed and range of motion. Examples include fishing rods, shovels, and tweezers.

​​

The derived SI unit of illuminance is the lux (lx).

• It is a type of air pollutant.
• It is derived from vehicular emission from internal combustion engines and industrial fumes that react in the atmosphere with sunlight to form secondary pollutants.
• In certain cities, such as Delhi, smog severity is often increased by stubble burning in neighboring agricultural areas.
• It is highly toxic to humans and can cause severe sickness, shortened life or death.

Explanation: 

If the removal of effort while lifting, results in lowering of the load, the machine is said to be reversible.

The machine is said to be self-locking if the load is not lowered on the removal of the effort.

Important Points

A lifting machine is reversible if its efficiency is greater than 50 per cent and self-locking if its efficiency is less than 50 per cent.

The correct answer is joule.

• The unit of heat in the SI system is Joule.
  • A unit of energy equal to the work done when a force of one newton acts through a distance of one meter.

Important Points

• The other common units for heat are-
  • BTU (Btu) - British Thermal Unit - also known as a "heat unit" in the United States.
  • Calorie: The amount of heat required to raise the temperature of one gram of water 1^oC.
• Erg is a unit of energy.
  • It equal to the force of one dyne over a distance of one centimeter.
  • 1 erg = 10^-7 joule.
• Watt is a unit (SI) of power.
  • It is equal to one joule of work performed per second.
  • 1 horsepower = 746 watt 

Key Points

• 1 joule = 0.14 calorie = 9.478 x 10^-4 Btu.
• 4.184 joule of heat energy (or one calorie) is required to raise the temperature of a unit weight (1 g) of water from 0^oC to 1oC, or from 32^oF to 33.8^oF.
• 1 dyne = 0.00001 newton.

The correct answer is 120-degree.

Key Points

• Draw horizontal and vertical lines to represent an isometric object.
• While horizontal lines are drawn at a 30-degree angle to the horizontal plane, vertical lines remain vertical.
• All three axes must be at a 120-degree angle from one another. Now, if you adhere to rule number 1, this is accomplished automatically.
• An object's three faces are all equally foreshortened in the isometric projection.
• Any mechanical drawing or system is typically explained with an isometric drawing.
• It can be found on instructions for model kits like Lego, Gundam, and others, as well as mechanical infographics. 

Key Points

• In Class 1 and Class 3 levers, the fulcrum or the force is located at one end, requiring support like a bearing or pivot to hold the beam in place.
• Class 1 lever has the fulcrum between the effort and the load (e.g., seesaw), which must be held with a pivot/bearing.
• Class 3 lever has the effort between the fulcrum and the load (e.g., tweezers), also requiring support to stabilize the beam.
• These types of levers need a fixed point or axis of rotation, which is typically provided by a bearing, hinge, or other support.
• Class 2 levers do not usually require a bearing to stabilize the beam in the same way, as the load lies between the effort and fulcrum (e.g., wheelbarrow).

Additional Information

• Class 1 Lever:
  • Fulcrum between load and effort.
  • Examples: Seesaw, scissors, crowbar.
  • Can multiply force or speed depending on fulcrum position.
• Class 2 Lever:
  • Load between effort and fulcrum.
  • Examples: Wheelbarrow, nutcracker.
  • Always multiplies force; mechanical advantage > 1.
• Class 3 Lever:
  • Effort between fulcrum and load.
  • Examples: Tweezers, tongs, human forearm.
  • Multiplies speed and distance; mechanical advantage < 1.
• Role of Bearings:
  • Bearings provide rotational support to the lever beam, minimizing friction.
  • Essential in systems where a stable pivot point is necessary.
• Mechanical Advantage:
  • Levers provide mechanical advantage by trading force for distance or vice versa.

• The greenhouse effect occurs when Earth's atmosphere traps solar radiation because of the presence of certain gases called green house gases.
• This results in an overall increase in the average temperature of the earth’s atmosphere.
• Some major greenhouse gases are- Carbon dioxide, Methane, Nitrous oxide, Chlorofluorocarbons, etc.