things to remember Flashcards
how does centripetal acceleration come about
Due to the gravitational force and contact force acting on it, they are in opposite directions and the resultant causes centripetal acceleration
why is the path of an object in orbit circular
the centripetal force is given by gravitational force which is perpendicular to velocity and causes centripetal acceleration
what happens when two like charges are put next to each other and they are able to move
-they repel each other
- their velocities are equal and opposite (COM)
- force decreases with distance so their acceleration
decreases
when drawing a graph of induced emf from flux density
The peak is where the gradient of the flux is steepest and when gradient =0 emf is 0
why doesn’t an electron follow a circular path when in a uniform electric field
-the force is not always perpendicular to velocity
- or force isn’t always in the same direction
why do dark lines when white light passes through a cloud of cool gas
-photons have discrete energy due to their wavelength
- match with one electron exciting it goes to a higher energy level
-electron de-excites emitting a photon in any direction causing the dark lines
how to calculate power in radioactivity
activity x energy in joules
what can be concluded about the universe due to an observed change in wavelength
objects are moving away,
-the universe is expanding
- the wavelength has increased due to redshift
why might the total amount of energy released in a decay process be greater than the calculated answer
gamma photons are also emitted
- the product has kinetic energy to conserve momentum
how do you calculate the energy needed to move a moving object from obit to infinity
Gravitational potential energy - kinetic energy
how does the value of mean power differ between full wave and half wave rectification
half wave is half full wave value
why might the transmitted intensity through a sample of two mediums be less than the calculate answer
- ultrasound is absorbed and reflected by matter in the medium
-there is more than one boundary so more reflectionswha
what can be concluded from the diffraction pattern of electrons about their nature
the beams spread which indicate diffraction and show they are wave like
if electrons are accelerated through a greater p.d. how would that change the diffraction pattern
-wavelength is inversely related to momentum
-increase in p.d. increases speed and momentum
-wavelength decreases causes a smaller diffraction angle
explain why at the surface of the sphere gravitational field is negative to displacement
g is always attractive
force is opposite direction to displacement
