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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
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Flashcard (63)