Kaplan FL1 Flashcards
Why would spacecraft decay in orbit?
it will colide with molecules in the upper atmosphere and loose kinetic energy causing its orbit to decay over time
If the human body has 400 resistance a device makes 160 V what is the current that flows through?
a rocket looses orbit and begins to fall. If rockets are started parallel to velocity then what happens to gravitational energy
because the rockets will gain height, gravitational potential energy increases
mgh
which region is least likely to show bright in MRI scan: kidney, eyes, femur, biceps
MRI relies of imaging of protons and brightness is proportional to density of protons in tissues.
The least likley to be bright means LEAST protons
most protons in tissues are in WATER… so which tissue has lowest water content
soft tissues like kidney muscle eyes have high water but bones have lower water
what is beta plus and beta minus decay?
radioactive decay: atomic nucleus emits a beta particle (fast energetic electron or positron) either pos or neg
beta plus - proton–> neutron which reduces atomic number by 1 (bottom in symbol)
beta minus - neutron –> proton which increases atomic number by 1
what is gamma decay?
gamma decay, type of radioactivity in which some unstable atomic nuclei dissipate excess energy by a spontaneous electromagnetic process.
neutrons and protons stay the same
is beta plus, beta decay, gamma affected by magnetic field?
beta come in pos and neg and as charged species are affected magnetic field when moving perpindicular
gamma radiation emits neutrons which are unaffected by magnetic field
Assume the central electrode and casing creates an electric field. If the distance increases between electrode and casuing is 2 cm what is the magnitude of electric field? how can you find the magnitude of electric field given voltage and distance
V = Ed
U = qdeltaV = qEd = kQq/r
qdeltaV = qEd
do photons move to anode or cathode? are they affected by electric field
photons have no charge and are NOT attracted to cathode or anode
they are neutral and move through field unaffected
a photon collides with an inonizes a helium atom, ejecting an atom with kinetic energy of 1.4 eV– if the atom was originally in ground state with ionizable potential 24.6 eV, what was the frequency of the original photon? (planks consant h = 4.14 * 19^-15 eV*s)
we need to find original photon energy
E = 24.6 (ionizable) + 1.4 (kinetic) = 26 eV
E = hf
f = E/h
f = 26/ (4.14*10^-15)
f = 6.3 *10^15 Hz
14C beta minus decay results in what atom?
beta minus increases atomic number by 1
keeps neutrons (14) same
c –> N
14C -> 14N
How do you transfer heat from the bath?
spontaneously transfer heat by adding a substance with a lower temperature than the ice bath (0 celcius - freezing point)
how do you find the amount of heat gained or lost by a sample?
q = mc delta T
q, heat in J
m, mass in kg
c, specific heat in J/gC
delta T, temp in C
what does it mean if
dissolution of O2 is exothermic (neg enthalpy)
the temp of surrounding will rise but eventually top off
when current increases through wire, magnetic field
INCREASES
