PHYSICS MISTAKES

describe the stages in the evolution of a star similar in mass to the sun (4)

• nebula to protostar

• protostar to main sequence

• main sequence to red giant

• red giant to dwarf

• white dwarf to black dwarf

energy release in stars

• NUCLEAR FISSION

• fusion of the joining of the nuclei

• involves light nuclei

energy release in reactors

• NUCLEAR FUSION

• splitting of the nuclei

• involves heavy nucleus

HOOKE’S LAW

• idea that extension is (directly) proportional to force or load

• up to limit of proportionality

why does a ray of light not change direction when it enters the atmosphere

• angle of incidence is 0

• therefore the angle of refraction is also 0

describe how a loudspeaker in the radio converts a.c. signal to a sound wave (4)

describe an experiment to determine the emission of technetium-99 is gamma radiation (5)

• use a GM tube

• measure background count rate

• measure count (rate) with source;

• subtraction to) find corrected count (rate);

• repeat readings to obtain mean;

• idea that paper / aluminium does not affect count / reading;

• idea that lead reduces count rate significantly;

explain how the doppler effect cuases a change in the observed frequency of the waves

• speed of waves constant;

• if source moving away, wavefronts spread out / wavelength increases;

• speed = frequency × wavelength;

• (higher wavelength and constant speed of waves) gives lower frequency;