This set of Engineering Metrology Multiple Choice Questions & Answers (MCQs) focuses on “Terminology”.
1. What does ‘50’ represents in 50H8/g7?
a) Basic size
b) Actual size
c) Maximum limit of size
d) Minimum limit of size
Explanation: 50 represent the basic size of the hole and shaft. H and g are the positions of tolerance zone with respect to zero line for hole and shaft respectively. 8 and 7 are the tolerance size.
2. What is ‘Go limit’?
a) Lower limit of shaft and upper limit of hole
b) Lower limit of shaft and hole
c) Upper limit of shaft and lower limit of a hole
d) Upper limit of shaft and hole
Explanation: ‘Go limit’ deals with upper limit of shaft and lower limit of hole and refers to the maximum material condition. ‘No-go’ limits deals with lower limit of shaft and upper limit of hole and refers to the minimum material condition.
3. Which of the following is incorrect regarding terminology?
a) Grades of tolerances decides manufacture’s accuracy
b) For any basic size there are 20 different shafts
c) Line of zero deviation is known as zero line
d) Tolerance has no sign
Explanation: For any basic size, there are 25 different shafts. These are designated by small letters from a to zc. Each shaft has 20 tolerance grades. Tolerance is the algebraic difference between lower and upper deviation.
4. What is the actual deviation?
a) Algebraic sum between actual size and corresponding basic size
b) Algebraic difference between actual and corresponding basic size
c) Average of actual and basic size
d) Algebraic difference between upper and lower deviation
Explanation: Algebraic difference between a size and a corresponding basic size is called deviation. Limit deviations are upper and lower deviations. Algebraic difference of actual size with basic size is called actual deviation.
5. What is the condition for a positive upper deviation?
a) Maximum limit of size > basic size
b) Maximum limit of size is < basic size
c) Minimum limit of size > basic size
d) Maximum limit of size < basic size
Explanation: Upper deviation is positive when maximum limit of size > its basic size and negative when maximum limits size < basic size. For lowers deviations, it is a positive quantity when minimum limit size is more than its corresponding basic size.
6. How many holes are there for any basic size?
Explanation: There are 28 different holes for any basic size. These are designated by capital letters. A, B, CD, C, D, E, EF, F, FG, G, H, JS, J, K, M, N, P, R, S, T, U, V, X, Y, Z, ZA, ZB, ZC these are the 28 holes.
7. What does ES represent in terminology as per IS: 919?
a) Lower deviation of hole
b) Upper deviation of shaft
c) Lower deviation of shaft
d) Upper deviation of hole
Explanation: ‘ES’ and ‘es’ represents upper deviation for hole and shaft respectively. ‘EI’ and ‘ei’ represents lower deviation for hole and shaft respectively.
8. What is ‘IT01’?
a) Basic size of hole
b) Basic size of shaft
c) Tolerance grade
d) Standard tolerance factor
Explanation: ‘IT’ refers to the standard tolerance which belongs to any standard grade of tolerance. Tolerance grades are designated by ‘IT’ letters followed by a number. For example, IT01 is a tolerance grade.
9. For tolerance grades 5 to 16, what is the formula for standard tolerance factor?
(D=mean diameter in mm)
a) 0.45 (D)1/3 + 0.001D
c) 0.45 (D)3 + 0.001 D
Explanation: For tolerance grades 5 to 16 the value of tolerance magnitude is in terms of standard tolerance factor, i = 0.45 (D)1/3 + 0.001 D. For grade IT6, tolerance is 10i. Above it, at each 5th step the tolerance magnitude is multiplied by 10.
10. What is the hole size which is covered by IT05?
a) 500 mm
b) 600 mm
c) 700 mm
d) 800 mm
Explanation: There are 7 finest tolerance grades from 1T01 to IT05. It covers sizes up to 500 mm. There are 11 coarsest grades which cover sizes up to 3150 mm. Tolerance grades depend upon shaft or hole size.
Sanfoundry Global Education & Learning Series – Engineering Metrology.
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