Measurement

Question 1

List the physical quantities

Answer 1

Length
Mass
Time
Temperature
Amount of substance
Electric Current

Question 2

Unit of each physical quantities

Answer 2

Length - Metre
Mass - Kilogram
Time - second
Temperature - Kelvin
Amount of substance - Mole
Electric Current - Ampere

Question 3

Tera

Answer 3

10^12

Question 4

Giga

Answer 4

10^9

Question 5

Mega

Answer 5

10^6

Question 6

Hecto

Answer 6

10²

Question 7

Deca

Answer 7

10¹

Question 8

Deci

Answer 8

10⁻¹

Question 9

Centi

Answer 9

10⁻²

Question 10

Milli

Answer 10

10⁻³

Question 11

Micro

Answer 11

10^-6

Question 12

Nano

Answer 12

10^-9

Question 13

Pico

Answer 13

10^-12

Question 14

Symbol of meter

Answer 14

m

Question 15

Symbol of Kilogram

Answer 15

Kg

Question 16

Symbol of second

Answer 16

s

Question 17

Symbol of Kelvin

Answer 17

k

Question 18

Symbol of amount of substance

Answer 18

Mol

Question 19

Symbol of Ampere

Answer 19

A

Question 20

How many mL in one L?

Answer 20

1000

Question 21

How many cm³ in 1L?

Answer 21

1000

Question 22

Formula for Celsius?

Answer 22

C = 5/9 (F - 32)

Question 23

Formula for Fahrenheit?

Answer 23

F = 9/5(c) + 32

Question 24

Formula for Kelvin

Answer 24

K = c + 273.15

Question 25

How many hours in a day

Answer 25

24

Question 26

How many minutes in an hour?

Answer 26

60

Question 27

How many seconds in a minute ?

Answer 27

60

Question 28

Define derived units?

Answer 28

This is a unit coined out by combining the basic units

Question 29

List the main Derived quantities

Answer 29

Area Volume Density Speed/Velocity Acceleration Force Pressure Energy

Question 30

Definition of area and unit

Answer 30

Length square - m²

Question 31

Definition of volume and unit

Answer 31

Length cubed - m³

Question 32

Define density and unit

Answer 32

Mass per unit volume - kg/m³

Question 33

Define speed/velocity and unit

Answer 33

Distance traveled per unit time ms⁻¹ or m/s

Question 34

Define acceleration

Answer 34

Velocity per unit time ms⁻² or m/s²

Question 35

Define force

Answer 35

Mass times acceleration Kg ms⁻² or N (newton)

Question 36

Define pressure

Answer 36

Force per unit area Kgm⁻¹s⁻² or N/M² or Pa

Question 37

Define energy

Answer 37

Force times distance travelled Kg m²/s² or J

Question 38

What digits are significant ?

Answer 38

Non-zero digit e.g 9.12 has 3 sig fig Zero when it’s between non-zero digits e.g 6.09 has 3 sig fig Zero when it’s at the end of a number that includes decimal point e.g 0.500 has 3 sig fig In Ax10ⁿ format where A shows the number of sig fig. E.g 7.00x10² has 3 s.f

Question 39

What digits are not significant?

Answer 39

Zeros before the first non-zero digit e.g 0.0108 has 3 s.f Zeros at the end of the number without a decimal point e.g 1000 has 1 s.f

Question 40

Rule for rounding off, five or greater.

Answer 40

When the first digit after those you want to retain is five or greater. That digit and those after it is dropped and the one before it is raised by one. 1.026868 to 4 digits = 1.027

Question 41

Rule for rounding off, four or less.

Answer 41

The digit after those u want retained and all other are dropped, with no change to the digit before.

Question 42

When performing arithmetic with sig figs, what should the final answer look like ?

Answer 42

The answer should be to the least number of sig figs in the data.

Question 43

Types of error

Answer 43

Determinate Error Indeterminate Error

Question 44

Define Determinate Error

Answer 44

This arise from artificial mistakes either on the part of the analyst or faulty equipments. They can be avoided or corrected.

Question 45

Ways to minimize determinate error

Answer 45

Calibration of apparatus Running of a blank determination Running of a control

Question 46

Indeterminate Error

Answer 46

Also called random error. These cannot be avoided, these represent experimental uncertainty that occurs in any measurement.

Question 47

Define precision?

Answer 47

This is the degree of closeness between a set of value obtained from identical measurements.

Question 48

Define Accuracy

Answer 48

This referred to the degree of closeness of a single measurement to its true value.

Question 49

Ways Accuracy is estimated?

Answer 49

Absolute Error Relative Error Percentage Relative Error

Question 50

Formula for least square estimate (arithmetic mean)

Answer 50

x̄ = sum of set of replicate / number of reading

Question 51

Formula for absolute error

Answer 51

€ = observed value - true value € = x - T ]- single measurement € = x̄ - T ]- replicate

Question 52

Formula for relative error ?

Answer 52

R = Absolute error / True value R = €/T

Question 53

Formula for percentage Relative Error

Answer 53

% = €/T * 100

Question 54

What is the formula for mean deviation?

Answer 54

D̄ = Σ|x - x̄| / N Mean deviation (Average Error) = Summation of Deviation from the mean / number of measurement

Question 55

What is the formula for mean deviation?

Answer 55

D̄ = Σ|x - x̄| / N Mean deviation (Average Error) = Deviation from the mean / number of measurement

Question 56

Formula for standard deviation when N is ≦ 30

Answer 56

S = √ ( Σ ( x - x̄ )² / N - 1)

Question 57

Formula for standard deviation when n > 30

Answer 57

S = √ ( Σ ( x - x̄ )² / N )