Measurements and Errors

Question 1

What is the symbol and the magnitude of the prefix: tera

Answer 1

T

×10^12

Question 2

What is the symbol and the magnitude of the prefix: giga

Answer 2

G

×10^9

Question 3

What is the symbol and the magnitude of the prefix: mega

Answer 3

M

×10^6

Question 4

What is the symbol and the magnitude of the prefix: kilo

Answer 4

k

×10^3

Question 5

What is the symbol and the magnitude of the prefix: centi

Answer 5

c

×10^-2

Question 6

What is the symbol and the magnitude of the prefix: milli

Answer 6

m

×10^-3

Question 7

What is the symbol and the magnitude of the prefix: micro

Answer 7

μ

×10^-6

Question 8

What is the symbol and the magnitude of the prefix: nano

Answer 8

n

×10^-9

Question 9

What is the symbol and the magnitude of the prefix: pico

Answer 9

p

×10^-12

Question 10

What is the symbol and the magnitude of the prefix: femto

Answer 10

f

×10^-15

Question 11

SI unit for Amount of substance

Answer 11

Mole/mol

Question 12

SI unit for Temperature

Answer 12

Kelvin/K

Question 13

SI unit for Length

Answer 13

Metre/m

Question 14

SI unit for Time

Answer 14

Second/s

Question 15

SI unit for Mass

Answer 15

Kilogram/kg

Question 16

SI unit for Current

Answer 16

Ampere/A

Question 17

What is a Systematic Error?

Answer 17

An error that causes the measurements to differ from the true value by the same amount

Question 18

What is a Random Error

Answer 18

An error caused by unpredictable circumstances and resulting in measurements that differ from the true value by varying amounts

Question 19

Sources of Systematic Errors

Answer 19

• Imperfect Calibration
• Imperfect Methods of Observation
• Interference from the environment

Question 20

Sources of Random Errors

Answer 20

• Mistakes made in inaccurate readings made by the experimenter
• Fluctuations in the reading on the instrument

Question 21

How do you reduce Systematic Errors?

Answer 21

• Repeating the experiment using a comparable apparatus to identify the source of the error
• Accurate calibration of equipment
• Confirming experimental method against literature

Question 22

How do you reduce Random Errors?

Answer 22

• Taking averages over multiple measurements, not including anomalous results
• Repeating the experiment and and averaging over all the measurements

Question 23

Define Error

Answer 23

The difference between the measured value and the true value of measurement

Question 24

Define Uncertainty

Answer 24

The degree to which we can say a measurement is accurate

Question 25

Define Accuracy

Answer 25

A measurement is accurate if its value is close to the true/accepted value

Question 26

Define Precision

Answer 26

A measurement is precise is its value is close to the average of measurements of the same quantity

Question 27

Define Repeatability

Answer 27

A measurement is repeatable if the experiment can be repeated to obtain the same results under the same conditions

Question 28

Define Reproducable

Answer 28

An experiment is reproducible if it can be reproduced by the same or an independent experimenter

Question 29

How do you calculate percentage uncertainty?

Answer 29

Absolute uncertainty/value × 100

σ = ε/a × 100