Practical Skills Y1

Question 1

List all seven base quantities and their abbreviations?

Answer 1

length - l, s, d;
time - t;
temperature - T;
mass m
amount of substance n;
electrical current I;
Luminosity L

Question 2

List all seven SI units and their symbols

Answer 2

Kilograms - kg
Metre - m
Seconds - s
Kelvin - K
Ampere - A
Mole - mol
Candela - cd

Question 3

Uncertainties Adding or subtracting

Answer 3

sum of absolute uncertainties

Question 4

Uncertainties Multiplied or divided

Answer 4

sum of percentage uncertainties

Question 5

Accuracy

Answer 5

if the results are very close to the accepted value

Question 6

Precision

Answer 6

The spread of repeated results - repeat results are very similar

Question 7

What is the correlation between precision and percentage uncertainty

Answer 7

the more precise the results the smaller the percentage uncertainty

Question 8

What is the reliability of an experiment?

Answer 8

Give consistent results each time the experiment is repeated - reliable results produce small scatter graphs

Question 9

What is resolution

Answer 9

smallest divisions on the measuring instrument

Question 10

How to calculate % difference

Answer 10

(measured value - true value)/truevalue * 100

Question 11

How to draw the line of worst fit?

Answer 11

add in the error bars - draw the line of worst fit by joining the bottom of the first error bar and the top of the last

Question 12

What are lines of worst fit used for?

Answer 12

To find the percentage uncertainty of the gradient

Question 13

How can random error be reduced?

Answer 13

repeating the measurements/experiments and calculating a mean

Question 14

What does repeating, and calculating a mean do in terms of error?

Answer 14

reduces random error

Question 15

What is a systematic error?

Answer 15

an error where the measured value deviates from the actual value by the same amount consistently
(eg zero error)

Question 16

What is random error?

Answer 16

errors in measurement caused by factors which vary with each measurement
(eg parallax error)

Question 17

When calculating averages with a table of given values what do you do to outliers?

Answer 17

IGNORE THEM

Question 18

How to convert squared and cubed prefixes to si? (you can use 1cm^3 as an example??

Answer 18

convert the prefix to a power, than multiply by the original power attached to the si unit;
In the case of 1cm^3 becomes x10^-6m^3 “

Question 19

When talking about precisions, how do you make a measurement more precise?

Answer 19

use instruments with greater resolution

Question 20

How do you make an experiment more reliable?

Answer 20

repeat and calculate a suitable mean

Question 21

Absolute uncertainty of a micrometer?

Answer 21

0.01mm

Question 22

Absolute uncertainty of a ruler?

Answer 22

0.001m (1mm)

Question 23

When asked to plot something, what must be done?

Answer 23

plot crosses as well as line/curve of best fit (same number of points either side of line of best fit)

Question 24

How to calculate an absolute uncertainty?

Answer 24

take the range of values given and divide by 2

Question 25

Why must ruler measurements be taken to three decimal places in meters?

Answer 25

measures to the nearest mm

Question 26

How to find absolute uncertainty?

Answer 26

Calculate a maximum value of the experiment
Calculate maximum minus average value

Question 27

When calculating uncertainty, how many decimal places do you do it to?

Answer 27

same dp as average

Question 28

What does T mean as in 60TW?

Answer 28

T means Tera which is the same as 10^12

Question 29

What does G mean as in 3GJ?

Answer 29

G means Giga which is the same as 10^9

Question 30

What does M mean as in 8MV?

Answer 30

M means Mega which is the same as 10^6

Question 31

What does k mean as in 7km?

Answer 31

k means kilo which is the same as 10^3

Question 32

What does c mean as in 12cm?

Answer 32

c means centi which is the same as 10^-2

Question 33

What does m mean as in 2mA?

Answer 33

m means milli which is the same as 10^-3

Question 34

What does µ mean as in 12µA?

Answer 34

µ means micro which is the same as 10^-6

Question 35

What does n mean as in 0.2nm?

Answer 35

n means nano which is the same as 10^-9

Question 36

What does p mean as in 2ps?

Answer 36

p means pico which is the same as 10^-12

Question 37

Where do I get the true value from?

Answer 37

Databook or manufacturer’s value