A level physics 1 markers

aqa

define resistivity

what is a transverse wave?

what is a longitudinal wave?

eqn for how to find % uncertainty for a gradient?

((best fit - worst fit)/best fit)x100

what are the two types of error?

random error and systematic error

what is meant by a standard candle?

object whose absolute magnitude is known and whose apparent magnitude can be measured

what is the area under a pressure volume graph?

work done

what are the prominent absorption lines for an O spectral class?

He⁺, He, H

explain how eddy currents arise

changing magnetic friends in the core result in emf in the core. current flows as core is made from conducting material.

what are the prominent absorption lines for an A spectral class

H (strongest), ionised metals

what is the binding energy of free nucleons?

0

What’s the colour of a star with spectral class O?

blue

what’s the temperature of a star with spectral class O?

25000-50000K

ideal location for optical telescopes?

terrestrial and away from populations (atmosphere is transparent to waves)

define the apparent magnitude

brightness as seen from earth

how do you combine potentials?

add them (they’re scalar)

what is the main source of waste in a thermal nuclear reactor?

radioactive daughter nuclei from the fission of uranium 235

what happens to amplitude and frequency under damping?

they decrease

give a suitable site for radio telescopes

terrestrial (as large and heavy)

away from population centres (to avoid interference)

which waves cannot be polarised?

ultrasound, longitudinal

range of alpha radiation in the air?

0.004m

ideal location for UV telescope and why?

in space as UV waves absorbed in upper atmosphere

what is constant in a capacitor if it is disconnected?

charge

what are the kinetic theory of gas assumptions?

molecules are point masses

molecules have no intermolecular attractions

molecules move in continual random motion

molecule collisions are perfectly elastic

molecule collisions with container calls are significantly shorter in duration than time in between impacts

3 things necessary for a standing wave?

same frequency

travel in opposite directions

same speed

where does a black body disagram start?

not the origin as it’s not a perfect absorber of radiation (on x-axis)

2 ads of using electrons instead of alpha particles to find nuclear radius?

higher resolutions as wavelength can be made very small

alpha particles only give upper limit of radius (distance of closest approach)

what do control rods do?

limit number of neutrons in the reactor (by absorbing neutrons without causing fission)

how was the universe discovered to be expanding?

distance measured through comparison of standard candles and inverse square law

red shift shows velocity of galaxies further away is greater

all galaxies are moving away from each other so the universe is expanding

why is there an increase in energy stored on a capacitor when the dielectric is removed?

in the polar dielectric molecules align +ve to -ve plate

work is done separating the +ve surface of the dielectric from the -ve charge place (vice versa)