Practical skills Flashcards Preview

13 old > Practical skills > Flashcards

Flashcards in Practical skills Deck (20)
Loading flashcards...
1

When calculating an answer what is the appropriate number of significant figures to give your answer in?

The same as the value in the question with less number of significant figures.

2

State the uncertainty when using vernier callipers

0.1 cm

3

State the uncertainty when using a micrometer

0.1 mm

4

Define repeatable

When the person carrying out the experiment obtains similar results

5

Define reproducible

When another group carry out the experiment and obtain a similar pattern in their results

6

Define resolution

The smallest change an instrument can detect or display

7

Define accurate results

When the measured quantity has a value close to the true value

8

Define precision

When repeat readings have a small spread in the data

9

Define uncertainty

How accurately you can take a measurement or an expression of the spread of values taken.

10

How can you find the uncertainty in a single measurement

Your estimate using the precision of the equipment as a guide

11

How can the uncertainty be calcualted when you have repeat readings?

Range / 2

12

When an equation has addition or subtraction can you add the uncertainty or percentage uncertainty?

uncertainty

13

When an equation has multiplication or division can you add the uncertainty or percentage uncertainty?

percentage uncertainty

14

Define percentage uncertainty stating its equation

It is the percentage error in your measurements.

Percentage uncertainty = uncertainty / mean value (x100%)

15

Explain how you can find the percentage uncertainty in a gradient

  1. Find the gradient of the best line of fit.
  2. Draw a worst case LOBT and find its gradient.
  3. Calculate the percentage difference between the two values.

16

Explain how you can find the percentage uncertainty in an intercept

  1. Find the intercept from the best line of fit.
  2. Draw a worst case LOBT and find its intercept.
  3. Calculate the percentage difference between the two values.

17

Define a reading

The value is found from a single judgment when using a piece of equipment. e.g. thermometer, measuring cylinder. the uncertainty is given as half the precision

18

Define a measurement

The value taken as the difference between the judgement between two values e.g. ruler.

The uncertainty is given as half the precision x by 2

19

Define random error

Is an error that is different for every reading. This causes repeat readings to spread around the true value and scatter around the line of best fit

20

Define systematic error

The same error on all readings. It will shift all results and gradient up or down.