Physics A-level required information

When is a measurement valid?

when it measures what it is supposed to be measuring

When is a result accurate?

when it is close to the true value

What are precise results?

when repeat measurements are consistent/agree closely with each other

What is repeatability?

how precise repeated measurements are when they are taken by

the same person, using the same equipment, under the same conditions

What is reproducibility?

how precise repeated measurements are when they are taken by different people, using different equipment

What is the uncertainty of a measurement?

the interval within which the true value is expected to lie

Define measurement error

the difference between a measured value and the true value

What type of error is caused by results varying

around the true value in an unpredictable way?

random error

What is a systematic error?

a consistent difference between the measured values and true values

What does zero error mean?

a measuring instrument gives a false reading when the true value should be zero

Which variable is changed or selected by the

investigator?

independent variable

What is a dependent variable?

a variable that is measured every time the independent variable is changed

Define a fair test

a test in which only the independent variable is allowed to affect the

dependent variable

What are control variables?

variables that should be kept constant to avoid them affecting the dependent variable

What is an atom made up of?

a positively charged nucleus containing protons and neutrons, surrounded by electrons

Define a nucleon

a proton or a neutron in the nucleus

What are the relative charges of protons, neutrons, and electrons?

1, 0, and -1 respectively (charge relative to proton)

What are the relative masses of protons, neutrons, and electrons?

1, 1, and 0.0005 respectively (mass relative to proton)

What is the atomic number of an element?

the number of protons

Define an isotope

isotopes are atoms with the same number of protons and different numbers of neutrons

Define gamma radiation

electromagnetic radiation emitted by an unstable nucleus

What particles make up everything in the universe?

matter and antimatter

Name the antimatter particles for electrons, protons, neutrons, and neutrinos

positron, antiproton, antineutron, and antineutrino respectively

What happens when corresponding matter and antimatter particles meet?

they annihilate (destroy each other)

List the seven main parts of the electromagnetic spectrum from longest wavelength to shortest

radio waves, microwaves, infrared, visible, ultraviolet, X rays, gamma rays

Write the equation for calculating the wavelength of electromagnetic radiation

wavelength = speed of light / frequency

Define a photon

a packet of electromagnetic waves

Write the equation for calculating photon

energy photon energy (E) = Planck constant (h) x frequency (f)

Name the four fundamental interactions

gravity, electromagnetic, weak nuclear, strong nuclear