more conductor etc Flashcards
what are the features of a conductor (3)
- no energy gap
- highly conductive
- one or more bands are partially filled
what are the features of an insulator (4)
- large energy gap
- valence band is full
- at room temperature there is not enough energy to move electrons from the valence band into the conduction band
- no electrical conduction
what are the features of a semi-conductor (3)
- small energy gap
- at room temperature there is sufficient energy to move electrons from the valence band to the conduction band
- increase in temperature increases the conductivity of the semi-conductor
what does forward bias do to a p-n junction
reduces the electric field
how to decrease random uncertainties
- use a meter with smaller divisions
- take more readings of data
what velocity can be worked out using the doppler equation (3)
- velocity of source
- velocity of light
- the radial velocity of a star moving directly towards or away from an observer
how do u determine the temperature of a stellar object?
measure the peak wavelength of radiation emitted by the star
define projectile motion
constant horizontal velocity and constant vertical acceleration
what do crosses mean in a magnetic field
going into the page
what do dots mean in a magnetic field
going out of the page
how much light gets through a prism
100%
how much light goes through a grating
not all / not 100%
does red light diffract the least or the most
most
does red light refract least or the most
least
what does equation W=QV stand for
work done = charge x voltage
why does a nuclear fission reaction release energy
there is a loss in mass which is converted into energy
m x wavelength = ?
path difference
why is AC current used in a particle accelerator
so that the particles remain accelerating in the same direction ( if DC was used the electron would be attracted back to the positive side)
is the observed length longer or shorter than the actual length of an object
shorter because you multiply the length by a number less than 1!!!!
hotter starts are —-1—- emitting more light at a —–2— wavelength, —-3—- frequency.
1 bluer 2 short 3 high
