SS Flashcards
what happens to kinetic energy during breaking
heating to surroundingd
longest wavelength
red
Explain why an infrared remote control may not switch on the television from behind an armchair but a radio wave remote control always will.
infrared will absorb, blocked, radio go through. have different frequencies
transerve waves
moves up and down, right angles
wave speed formula
frequency x wavelength
radioactivty measure?
geiger
2 sources of background radiation?
sun ,or waste
Explain what happens in a carbon-14 nucleus when it decays to a nitrogen-14 nucleus
neutron decays to proton, beta emitted.
Describe how a student could use the semi-circular glass block and other
apparatus to determine the critical angle for a glass-air boundary
shine ray light into block,
through curved face radius,
change angle, until 90,
measure angle of incidence, repeat
how can student extend to find average speed
measure appropriate distance, time use formulas
A object is moving at constant speed. Explain why it is not moving with constant velocity.
Velocity is a vector, which has direction, which also changes
Explain why fluorine-18 must be produced close to the hospital where it is used.
Has short half-life, used ASAP, after making
Explain why the source of alpha radiation is usually inside the body but the
source of gamma radiation can be outside the body
Alpha is a short range, so needs to be close to tumour, gamma is long range, so can get into body, from outside.
compare radio and gamma
radio made intentionally, gamma randomly.
radio produced by free electrons, produced in aerials.
gamma from decay, annihilations, due to fission or fusion
process for fusion in new star
nebula collapse, due to gravity, GPE turned into KE.
Evidence for expansion
red shift light from distance stars shifted to red side of EM wavelength of light is long source mioving away, galaxies show expanding increasing rate
evidence for beginning at point
CMBR
mirowave radiation left over from begin
increase of velocity with distance
detected from all over sky
Describe what is meant by red-shift.
frequency decreasing, star moving away
Explain how red-shift provides evidence for the Big Bang theory.
Red shift is further galaxy, more red shifted light is, further galaxies, faster moving, provides evidence space is expanding.
White light can split into colours of spectrum. Why in terms of speed?
colours= different wavelengths.
colour=different speeds
refracts in different
amounts
In a fusion reaction, two hydrogen nuclei are forced together to form a
helium nucleus. Explain why a very high temperature is needed for this reaction to happen.
High temperature means high energy, overcome force of repulsion, due to having same charge.
Explain how the graphite core and the movable rods are used to maintain and control the chain reaction.
neutrons releasedf slower neutrons needed for fission, some fast, control rods move in out, control speed of reaction. graphite cord (moderator), slows neutrons. moveable, absorb neutrons, make more or few available for fission
Describe difference between transverse and longitudinal waves?
transverse has oscillations perpendicular to waves, longitudinal have same direction.
How to determine frequency of waves?
measure time 4 waves, to pass fixed point.
Frequency=number of waves/times
Explain why red shift supports both theories, but CMB supports only 1?
Both theories predict expanding universe, big bang predicts had beginning, red shift both support expanding, CMB indicates universe, support big bang.
half life>
Time taken for activity radioactive isotope to halve
How absorbing electron affects proton, and nucleon number of nucleus?
Proton number decreases by 1, mass remains unchanged
How can determine average speed of a trolley?
Measures of time between 2 positrons, using stopwatch, measurement of suitable distance, along runway, measurement of vertical height, repeat, find averages, use of correct equation.
Create experiment, investigate effect of different surfaces on average speed of trolley
Keep same height, slope, starting point, length of surface, use at least 3 or more surfaces, calculate average speed and repeat.
How a reduction in these industrial processes affect temperature of atmosphere
soot make ice black, absorb more infrared radiation
black cause increase temperature, earth absorption of IR, increase in temp.
Reduction in soot, reduce global warming. shiny sulfate, reflect IR radiation
Explain how fission of uranium-235 can lead to chain reaction
Causes 2 or 3 neutrons to be release, one or more of these neutrons absorbed by other nuclei, causes further fission of nuclei, releases further, chain
nuclear reactor not controlled
reaction slows, fewer fission, impact nucleus, as 1 released.
Describe how energy released is used to drive turbine?
Reactant surrounded by coolant, thermal energy from chain reaction heats, hot coolant used generate steam, used to drive turbine/
Explain how a nebula may evolve into a main sequence star.
Nebula as cloud of gas, pulled towards each other, temperature increases, enough for nuclear fusion.
