# Engineering Drawing Questions and Answers – Types of Scales – 2

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This set of Engineering Drawing online quiz focuses on “Types of Scales – 2”.

1. What are the two parts of the Vernier scale?
a) Primary scale and secondary scale
b) Plain scale and comparative scale
c) Vernier scale and secondary scale
d) Primary scale and Vernier scale

Explanation: The Vernier scale consists of two parts. They are the primary scale and the Vernier scale. Vernier scale is used to read very small dimensions with great accuracy. The Vernier part of the scale is derived from the primary scale.

2. Which of the following scale is a plain scale with fully divided minor divisions?
a) Diagonal scale
b) Vernier scale
c) Primary scale
d) Comparative scale

Explanation: The primary scale is a plain scale with fully divided minor divisions. For reading very small dimensions, minor divisions cannot be further divided. Hence we use a Vernier scale to read those dimensions.

3. The graduations of which scale is derived from the primary scale?
a) Comparative scale
b) Vernier scale
c) Plain scale
d) Diagonal scale

Explanation: The graduations on the primary scale helps in making the graduations on the Vernier scale. For reading very small dimensions we need to further divide the minor divisions on the primary scale, which will to problems in reading dimensions properly. Hence the Vernier scale is used.

4. Which of the following is used in checking the instruments to measure angles with great accuracy?
a) Circular Vernier scale
b) Plain scale
c) Diagonal scale
d) Comparative scale

Explanation: The circular Vernier scale is used to check the instruments to measure angles with high accuracy. They are used in measuring instruments like micrometer in mechanical engineering. They work on the same principle as the linear Vernier scale.

5. Which of the following scales represent two different units having the same representative fraction?
a) Plain scale
b) Diagonal scale
c) Comparative scale
d) Vernier scale

Explanation: Comparative scales are those in which two different units are measured by using different graduations but have a same representative fraction. A drawing can be read in two units with the help of this scale.

6. What is the length of the scale, the representative fraction is 1:50000 and the scale must measure up to 25 km?
a) 5 x 10-4 cm
b) 50 cm
c) 5 cm
d) 0.5 cm

Explanation: The formula for calculating the length of the scale is given by, Length of the scale = R.F. x maximum length to be measured; Hence length of the scale = 1 ÷ 50000 x 25 x 1000 x 100 = 50 cm. It is very important to note the units while calculating.

7. In a particular drawing, 40 inches is represented by a 10 cm long line. A comparative scale is constructed that measures up to 180 inches and 2 m respectively. What are the lengths of scale for both the inches as well as the meter scales? (1 inch = 0.0254 meter)
a) 7 cm and 8.3 cm
b) 35 cm and 18.35
c) 2.2 cm and 22.9 cm
d) 45 cm and 19.7 cm

Explanation: The length of the scale = R.F. x maximum length to be measured. Hence for the inches scale, R.F. = 10 ÷ 40 and the maximum length to be measured is 180 inches. Hence length of inch scale = 10 ÷ 40 x 180 = 45 cm. Similarly length of meter scale = 10 ÷ 40 ÷ 0.0254 ÷ 100 x 2 x 100 = 19.7 cm.

8. Which of the following is used to set or measure angles when a protractor is not available?
a) Plain scale
b) Diagonal scale
c) Scale of chords
d) Comparative scale

Explanation: The scale of chords is used to measure or set angles when there is no protractor. In this method, a line PQ is drawn and then from Q a perpendicular QR is drawn. An arc is drawn with centre Q and is made to intersect perpendicular QR. Then the arc is divided into 9 equal parts with each part denoting 10˚ from Q.

9. In a map, 30 miles is represented by 20 cm. What is the length of the kilometer scale if the maximum length to be measured is 10 km? (1 mile = 1.609 km)
a) 4.14 cm
b) 10.73 cm
c) 9.32 cm
d) 24.14 cm

Explanation: The formula for calculating the length of the scale is given by; Length of the scale = R.F. x maximum length to be measured. Hence from the formula, length of the scale = 20 ÷ (30 x 1.609 x 1000 x 100) x 10 x 1000 x 100 = 4.14 cm.

10. What is the representative fraction of the kilometer scale if 20 miles is represented as 5 cm and maximum length to be measured is 5 km? (1 mile = 1.609 km)
a) 1:4
b) 1:643600
c) 1:1.287
d) 0.7768:1

Explanation: The representative fraction is calculated by the formula, R.F. = length of the drawing ÷ actual length of the object. Here the length of the drawing is 5 cm and the actual length is 20 miles. In R.F. both quantities should be in the same unit. R.F. = 5 ÷ (20 x 1.609 x1000 x 100) = 1:643600.

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