A-Level Physics: Working as a Physicist: Overview

what is an SI unit?

fundamental units which are used alongside base quantities

what is the SI unit of mass?

kilogram (kg)

what is the SI unit of length?

metre (m)

what is the SI unit of time?

second (s)

what is the SI unit of current?

ampere (A)

what is the SI unit of temperature?

kelvin (K)

what is the SI unit of an amount of substance?

mole (mol)

what is the SI unit of luminous intensity?

Candela (cd)

what are derived quantities?

quantities which are made from base SI quantities

how can SI units be derived?

using their equation

what is an example of a unit being derived from an equation?

unit of force is derived by F=ma, F=kg x ms^-2, so F is kms^-2

what is the value of tera?

10^12

what is the value of giga?

10^9

what is the value of mega?

10^6

what is the value of kilo?

10³

what is the value of centi?

10^-2

what is the value of milli

10^-2

what is the value of micro?

10^-6

what is the value of nano?

10^-9

what is the value of pico?

10^-12

what is the value of femto?

10^-15

what is the name of 10^12?

tera

what is the name of 10^9?

giga

what is the name of 10^6?

mega

what is the name of 10³?

kilo

what is the name of 10^-2?

centi

what is the name of 10^-3?

milli

what is the name of 10^-6?

micro

what is the name of 10^-9?

nano

what is the name of 10^-12?

pico

what is the name of 10^-15?

femto

what is estimation?

skill used to approximate values of physical quantities

what is estimation used for?

to make comparisons or to check if a calculated value can be deemed reasonable

how can estimation be done?

rounding values up or down, as appropriate

what do random errors affect?

precision

what is meant by random errors affecting precision?

they cause differences in measurements which causes a spread about the mean

can you get rid of random errors?

no

how can random errors be reduced?

take at least 3 repeats of measurements and find a mean, use computer loggers to avoid human error and enable smaller intervals, use appropriate equipment

what do systematic errors affect?

accuracy

what can cause systematic errors?

apparatus or faults in experimental method

what is a consequence of systematic errors?

all results can be too high or too low by the same amount each time

how can a systematic errors be reduced?

calibrate apparatus by measuring a known value, correct for background radiation during radiation experiments

what is an uncertainty?

the bounds in which the accurate value can be expected to lie

what is the absolute uncertainty?

uncertainty given as a fixed quantity i.e 3±0.5V

what is the percentage uncertainty?

uncertainty as a percentage of a measurement i.e 3±17%

how can uncertainty be reduced?

measure larger quantities

what is a reading?

where one value is found

what is the uncertainty of a reading?

± half the smallest division

what is a measurement?

where the difference between two readings is found

what is the uncertainty of a measurement?

at least ±1 smallest division

to what significant figure should an uncertainty be given to?

the same number of significant figures as the data

what is the uncertainty for repeated data?

half the range

what is the uncertainty of a digital or given reading?

± the last significant digit

how do you combine uncertainties for added or subtracted data?

add the absolute uncertainties

how do you combine uncertainties for multiplied or divided data?

add the percentage uncertainties

how do you combine uncertainties for data raised to a power?

multiply percentage uncertainty by power

what is meant by an application of science?

use of scientific knowledge in order to carry out a specific action

what is meant by an implication of science?

a direct or implied consequence of the knowledge of a particular concept

what are the different kinds of implications of science?

commercial, legal, ethical, social

what is commercial implication?

implication concerning money

what is legal implication?

implication concerning the law

what is ethical implication?

implication concerning moral principles

what is social implication?

implication concerning society

In accordance to what is knowledge and understanding of a scientific concept changed?

experimental evidence gathered by scientific community

what must happen to experimental evidence before it is accepted?

must be published, peer reviewed and validated