3.1 Measurements and their errors

Question 1

What is a newton in SI base units?

Answer 1

kg.m.s-2

Question 2

What is a pascal in SI base units?

Answer 2

kg.m-1.s-2

Question 3

What is a joule in SI base units?

Answer 3

kg.m2.s-2

Question 4

What is a watt in SI base units?

Answer 4

kg.m2.s-3

Question 5

What is a coulomb in SI base units?

Answer 5

s.A

Question 6

What is a volt in SI base units?

Answer 6

kg.m2.s-3.A-1

Question 7

What are all the prefixes in descending order?

Answer 7

Deca
Tera
Giga
Mega
Kilo
Milli
Micro
Nano
Pico
Femto

Question 8

What is a random error?

Answer 8

An error in measurement caused by factors which vary from one measurement to another.

Question 9

What is a systematic error?

Answer 9

An error having a non-zero mean, so that its effect is not reduced when observations are averaged.

Question 10

What is a reading?

Answer 10

A value found from a single judgement.

Question 11

What are some examples of equipment that take readings?

Answer 11

Thermometer
Top pan balance
Measuring cylinder
Digital meter
Geiger counter
Pressure gauge

Question 12

What are some examples of equipment that take measurements?

Answer 12

Micrometer
Ruler
Vernier capiller
Protractor
Stowpwatch
Analogue meter

Question 13

How do you calculate the absolute uncertainty for a reading?

Answer 13

Half the finest increment on the device.

Question 14

How do you calculate the absolute uncertainty for a reading?

Answer 14

The finest increment on the device.

Question 15

How do you calculate the percentage uncertainty?

Answer 15

(Absolute uncertainty)/ (reading) *100

Question 16

How do you combine the uncertainty when adding 2 quantities together?

Answer 16

Add the absolute uncertainties

Question 17

How do you combine the uncertainty when multiplying or dividing 2 quantities?

Answer 17

Add the percentage uncertainties

Question 18

How do you combine the uncertainty when raising a quantity to the power n?

Answer 18

Multiply the percentage uncertainty by n

Question 19

Which value in a calculation adds the most to the uncertainty of the answer?

Answer 19

The value with the largest percentage uncertainty.

Question 20

What happens to the uncertainty when multiplying or dividing by a constant?

Answer 20

The absolute uncertainty is multiplied or divided too but, the percentage uncertainty remains the same.

Question 21

What is precision?

Answer 21

The closeness of two or more measurements to each other

Question 22

What is repeatable?

Answer 22

The original experimenter repeats the investigation using same method and equipment and obtains the same results

Question 23

What is reproducible?

Answer 23

The investigation is repeated by another person, or by using different equipment or techniques, and the same results are obtained

Question 24

What is resolution?

Answer 24

The smallest change in a quantity that an instrument can detect

Question 25

What is accuracy?

Answer 25

The closeness of a measured value to a standard or known value

Question 26

What is exponential decay?

Answer 26

A relationship in which a constant change in x gives the same proportional change in the y.

Question 27

What is exponential change?

Answer 27

A relationship in which the rate of change of the dependent variable is proportional to the value of the dependent variable.

Question 28

What is the general equation for an exponential?

Answer 28

y=kn^x

If 1<n there’s exponential growth
If 0<n<1 There’s exponential decay

Question 29

What is the exponential decay equation in physics?

Answer 29

y = y ₀e^(- λ * x)
Where λ is the decay constant

As when y = e^x the gradient is equal to the y value.