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

Explanation:

Universal Bevel Protractor Vernier Scale

Definition: A Universal Bevel Protractor is a precision instrument used for measuring angles with high accuracy. It consists of a base, a graduated circular scale, and a vernier scale that allows for fine measurements. The vernier scale is an essential part of the protractor, enabling users to measure angles to a finer degree than the main scale alone.

Understanding Vernier Scale: The vernier scale on a Universal Bevel Protractor is designed to provide precise readings of angles. This scale typically consists of a number of divisions that correspond to fractional parts of the main scale divisions. By carefully aligning the marks on the main scale and the vernier scale, users can read angles to a finer resolution.

Number of Divisions: The number of divisions on the vernier scale of a Universal Bevel Protractor is 24. This means that the vernier scale is divided into 24 equal parts. Each division on the vernier scale represents a fraction of the smallest division on the main scale, allowing for precise measurement of angles.

Working Principle: When measuring an angle using the Universal Bevel Protractor, the main scale provides a coarse measurement, while the vernier scale provides a fine measurement. To read the angle, users first note the main scale reading where the zero mark of the vernier scale aligns. Then, they find the vernier scale division that aligns most closely with any division on the main scale. The combination of these readings gives the precise angle.

Advantages:

• High precision: The vernier scale allows for measurements with high accuracy.
• Ease of use: The design of the Universal Bevel Protractor makes it straightforward to measure angles accurately.
• Versatility: It can measure a wide range of angles, making it useful in various applications.

Disadvantages:

• Delicate: The precision nature of the instrument means it can be sensitive and prone to damage if not handled carefully.
• Learning curve: Users may need practice to become proficient in reading the vernier scale accurately.

Applications: Universal Bevel Protractors are commonly used in fields requiring precise angle measurements, such as machining, metalworking, and carpentry. They are essential tools in quality control processes and are used by professionals to ensure the accuracy of manufactured parts and assemblies.

Explanation:

The unit conversions are shown in the table below.

Now We know that,

1 inch = 25.4 mm = 2.54 cm

1 meter = 39.37 inch

Concept:

Steel Rule

• It is a straightedge with equally spaced markings along its length.
• It is used to measure distances or to rule straight lines.
• It is available in different lengths, the common sizes being 150 mm, 300 mm, and 600 mm.
• Its reading accuracy (least count) is 0.5 mm or 1/64 inch.​

Important Points 

A micrometer may have a least count of 0.01 mm while a Vernier scale on a caliper may have a least count of 0.02 mm.

Explanation:

Shrink rule:

• The shrink rule is a special type of rule which is used to ease pattern-making.
• Shrink rule is used for laying out casting patterns and core boxes by pattern makers.
• The shrink rule looks like a simple rule, just the graduation on it is bigger than a simple rule because shrinkage allowance is added to each division of the shrink rule.
• It is used while making a pattern or core box.
• This type of steel rule is like a standard rule.
• The only difference is that its inch or mm markings are slightly larger than the standard rule.
• If the shrinkage allowance is 10 mm per meter of length, the 30 cm shrinkage scale will be 3 mm longer than the normal measuring scale.
• Different shrink rules are used for different pattern materials.
• It is also known as the contraction scale or shrinkage scale or pattern makers scale.
• This scale provides a ready-made method of assigning shrinkage allowances to a pattern.
• This type of rule is mostly used by pattern makers.
• Shrink rule is mostly made of steel or wood.

Hook rule:

• A reversible, removable hook grabs the edge of an object for easy alignment.
• Also known as machinists' rules, these rulers ensure reliable, repeatable measurements.
• A hook grabs the edge of an object for easy alignment.
• These rulers are corrosion-resistant stainless steel and have wear-resistant etched markings.
• All are flexible for measuring slightly curved surfaces.

Short steel rule:

• This set of five small rules together with a holder is extremely useful for measurements in confined or hard-to-reach locations which prevents the use of ordinary steel rules.
• It is used suitably for measuring grooves, short shoulders, recesses, keyways, etc. in machining operations on shapers, millers, and tool and die work.

Flexible rules:

•  Flexible rules are usually half an inch wide and 1/64 inch thick.
• While most steel rules are 12 inches long, they are available up to 144 inches (12 feet) long.
• It is capable of being bent, usually without breaking.
• A tape measure or measuring tape is a flexible ruler used to measure length or distance.

Explanation:

Linear measurement:

• When we measure an object, we are actually comparing it with a known standard of measurement.
• The base unit of length as per Systems International (SI) is a meter.
• 1 meter(m) = 1000 mm
• 1 centimeter (cm) = 10 mm
• 1 millimeter (mm) = 1000 μ
• 1 micrometer or micron (μm) = 0.001 mm
• One meter is approximately equal to 39.37 inches.

CONCEPT:

• Joule is a SI unit of energy or work done which is represented by J
• Watt is a S.I unit of Power and it is represented as W

\(Power\;\left( {Watt} \right) = \frac{{Work\;\left( {Joule} \right)}}{{time\;\left( {sec} \right)}}\)

Work done (J) = power (Watt) × time (sec)

1 joule = 1 watt. Sec

CALCULATION:

Since 1 kW = 1000 W = 10³ Watt or W

And 1 hour = 60 min x 60 sec = 3600 sec

\(\therefore \;1\;kWh = {10^3} \times 3600 = 3.6 \times {10^6}\;J\)

Concept:

Steel Rule

• It is a straightedge with equally spaced markings along its length.
• It is used to measure distances or to rule straight lines.
• It is available in different lengths, the common sizes being 150 mm, 300 mm, and 600 mm.
• Its reading accuracy (least count) is 0.5 mm or 1/64 inch.​

Important Points 

A micrometer may have a least count of 0.01 mm while a Vernier scale on a caliper may have a least count of 0.02 mm.

Explanation:

Linear measurement:

• When we measure an object, we are actually comparing it with a known standard of measurement.
• The base unit of length as per Systems International (SI) is meter.
  • 1 meter(m) = 1000 mm
  • 1 centimeter (cm) = 10 mm
  • 1 millimeter (mm) = 1000 μ
  • 1 micrometer or micron (μm) = 0.001 mm
• Therefore, 10-2 mm is equal to 10-2 × 1000 = 10 microns.

Explanation:

Sag correction is given by:

\({C_s} = - \frac{{{{\left( {w L} \right)}^2}L}}{{24\;{P^2}}}\)

Where,

l = the length of the tape (in metres) suspended between supports

P = Pull applied in kg or N

W = weight of the tape in kg or N per metre run

Cs = Sag correction in metres for length (l)

wL = weight of tape suspended between the supports.

i) Sag correction is directly proportional to the square of the weight of the tape (kg per metre run)

ii) Sag correction is inversely proportional to the pull applied.

iii) While applying sag correction the catenary is approximated as parabola.

Explanation:

A Vernier depth gauge is a precision instrument, used to measure the depth of holes, recesses, slots, and steps within an accuracy of 0.02 mm.

• It consists of the following parts:
  • A - Beam
  • B - Base
  • C - Main Slide
  • D - jaw
  • E - Jaw clamp
  • F - Vernier scale
  • G - Main scale
  • H - Finer adjusting slide
  • I - Finer adjusting nut
  • J&K - Locking screws
  • L - Scriber blade

• The offset scriber in Vernier height gauge is an attachment that permits setting heights from the face of the surface plate.
• The beam is graduated with the main scale in mm.

Explanation:

We know that,

1 m = 100 cm = 1000 mm

1 μm (micron) = 10-6 m = 10-4 cm = 10-3 mm

So 4 micron = 4 × 10^-3 = 0.004 mm

Explanation:

The Vernier bevel protractor is a precision instrument meant for measuring angles to an accuracy of 5 minutes i.e. (1/12)° i.e. 12th part of 1° which is the value of each main scale division.

The Vernier bevel protractor has a main scale which is divided into 360 equal parts.

Each division is equal to 1°.

Explanation:

The unit conversions are shown in the table below.

Now We know that,

1 inch = 25.4 mm = 2.54 cm

1 meter = 39.37 inch

Explanation:

Cross-staff is used for setting out right angles and French cross-staff is an advanced version of cross-staff and can set out 45-degree angles also.

There are three types of cross-staff:

1. Open cross-staff
2. The French cross-staff and
3. The Adjustable cross-staff

Additional Information

The various instruments used in surveying and their purpose is given below in the tabulated form:

Given : -

Area of land on map, a = 30cm x 60 cm = 1800cm²

Scale of map, S₁ = 1/5000

Scale of topographical map, S₂ = 1/60000

Solution: -

Actual area of land,

\({A_{actual}} = \frac{a}{{S_1^2}} = \left( {1800 \times {{5000}^2}} \right)\)

Area of land on topographical map,

\({a_2} = {A_{actual}} \times S_2^2\)

⇒ \([{a_2} = \left( {1800 \times {{5000}^2}} \right) \times {\left( {\frac{1}{{60000}}} \right)^2} = 12.5\;c{m^2}\)