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A Level Physics > Working as a physicist > Flashcards

Flashcards in Working as a physicist Deck (20):
1

Femto

x10 ^-15

2

Pico

x10 ^-12

3

Nano

x10 ^-9

4

Micro

x10 ^-6

5

Milli

x10 ^-3

6

Kilo

x10 ^3

7

Mega

x10 ^6

8

Giga

x10 ^9

9

Tera

x10 ^12

10

What is uncertainty?

The interval in which the true value lies/the range of possible values

11

What is the error in a result?

The difference between the measured value and the true value

12

What is % uncertainty?

The uncertainty calculated as a percentage of the measured value

13

What is resolution?

The smallest measuring interval in a single reading. Resolution can give the uncertainty, but for instruments such as a stopwatch, human reaction time also contributes to uncertainty, so resolution cannot give uncertainty

14

What is the range?

The largest value minus the smallest value (in repeated readings)

15

What is precision?

Indicates the consistency between repeated values

16

Why is it better to measure larger values?

A larger value will give a much smaller percentage uncertainty, assuming the uncertainty is fixed

17

How should you estimate the uncertainty for a single measurement?

Given by half the smallest increment on the device. However, for instruments such as a ruler, the increment is the uncertainty, as 2 measurements are made.

18

How should you estimate the uncertainty for repeated readings?

Uncertainty is half the range, and % uncertainty is half range divided by mean

19

For calculated values, how should you combine uncertainties?

Add the % uncertainties (generally while multiplying or dividing results)

20

What is the purpose of error bars?

To visually represent the uncertainty, to allow a line of worst fit to be drawn which then allows for an uncertainty in the gradient to be calculated - difference between line of best fit and line of worst fit