Metrology

Question 1

What is metrology?

Answer 1

Science of MEASUREMENT and CALIBRATION

Question 2

Year metric system established in France?

Answer 2

1795

Question 3

Year French Bureau International des Poids et Mesures founded

Answer 3

1875

Question 4

Year National Physical Laboratory was founded

Answer 4

1900

Question 5

Traceability chain

Answer 5

Instrument - working standards - transfer standards - NPL

Question 6

What is BSI?

Answer 6

British Standards Institute

Holds all industrial standards for UK

Question 7

What is ISO?

Answer 7

International Organisation for Standardisation

Question 8

Define the metre

Answer 8

The pathlength travelled in 1/c seconds

Question 9

wavelegnth equation

Answer 9

v = lamda x f

Question 10

Rules for clocks

Answer 10

1) regular process or action to mark off equal increments of time
2) means of keeping track of this and displaying the results

Question 11

Quartz clock

Answer 11

uses piezoelectricity

Question 12

atomic clock

Answer 12

uses atomic resonance

and made of caesium-133

Question 13

number of counts =

Answer 13

time x frequency of operator

Question 14

roughness (Ra)

Answer 14

irregularities caused by CUTTING TOOL/PROCESS

Question 15

waviness

Answer 15

irregularities cause by MACHINE VIBRATION and deflections under CUTTING FORCE

Question 16

errors of form

Answer 16

departure from the geometrical shape

Question 17

Rz

Answer 17

maxiumum peak to valley height of profile

(sum of Zns)/n

Question 18

accuracy

Answer 18

deviation of reading from a known input

Question 19

precision

Answer 19

ability to reproduce reading with given acuracy

Question 20

error

Answer 20

difference between measured and known

Question 21

cosine errors

Answer 21

Tmeasured = Ltruecos(theta)

Question 22

sine errors

Answer 22

T = Lcos(theta) - sinA

Question 23

thermal expansion

Answer 23

= expansion/orginal length x temp change

Question 24

Abbe’s principle

Answer 24

E - I - L = Rtan(theta)

Question 25

metric thread notation

Answer 25

M(nominal diameter) x pitch