SS Flashcards
(34 cards)
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
