Mocks Exam Mistskes Flashcards
When talking about the electrons leaving capacitor, make sure to take what direction fincurrent
Not conventional
Avadgae current in the resistor?
Cslcuskte total charge
Divide by time between esch throw / discharge as this is average
Why does current not double roughly when you double frewuencyn
Because now the period is = to the time constsnt, meaning for every switch only 37 % can be discharged , and so as the capacitor cannot fully discharge this is why
How ti find time constsnt ridiculous PAG
Lit measure until 37 % and that’s it
Damon remember if resistance decreases, instils current Gina
Increase by same amount, but the time constsnt gonna. Decrease
When separation happens in a. Capacitor what happens
The capacistcne etc will change but the CHARGE WOMT CHAMHE
Even voltage etc will change but charge won’t, so energy dihbele
How ti find uncertainty using gradient s
Find a worst fit straight line throihgh error hard
Difference between edt and worst / best x 10
Uncertainties
Absolute is smallest reading , so ruler is 1 mm, vernier 0,1 etc
Adding subtract add absolute
Multiply dividing add percentage ucneritiaited
Repeated data, then half range (1/2 biggest - smallest)
And if it’s upper and lower bounds, find the value of upper and lower, and subtract and half it
Okay why good equipment
Because csn measure max
- time constsnt means percentage uncertainty less
- time constsnt means thst like 50s willmelapse before can’t make resdings anymore, which is ample enough readings ti make a graphs
Why voltsge the same
£ grown
Series, so charge swme, capacitance swme, gonna end up at swme viktsge
HOW TO DO ABSOLUTR FOR HRAOHS
Draw best fit calm
Now draw the worse fit from bottom of Ken to top of other
Find the difference in gradient , this is uncertainty
Unsure swme decimal
If horizontal force applied to circular motion what happens
Helical loop
Remember foil in MAGENTIC field experiences?
No current
Remmeber ti defibrillator difference. Egged. Age rich and electro field path
MAGENTIC decipher cieuclwr, elector parabolic
How does oscilloscope work
Time base hoxirntwl in s /cm
V vertical
Z easier peak to peak in oscilloscopes makes it easier
Remember that series batteries
Bath resistance and voltsge join
Transverse waves
Kogntifunal
All em
Waves on water
S waves earthquake
Sound wave s
Spring
P waves
Longtifunal waves already limited to one plane so can’t be polarise d
Diffraction wavelength doesn’t change but refraction if it went more dense then slows down so wvskentgh closer etc
Intensity = powe / area where are 4 oinr5
Itneekty ororptinsly to amplitude 2,
So when’s olitufr form to 9 superposition, so will intensity
Aerials can take differnt polarised waves by aligning so that less itjerefecne between waves will halogen form multiple statins
N = c/v
I meant if greater than critical angle it stays in vice Verca
Jessie erefrverice index,
Out light in semi circle so normal ways thst and it refracts across it, measure angle easily, and do itnutnilmirnrrfrscts across edge, then just measure angle sin of ti
Principle dof superposition
When two meet the vector addition fo theirndispclsmentd
So if meet in Lahore will supoerpose ti producencinsturuiv eitneferenc emf maximum amplitude and itnneidty thusnicncrewses
But if wnutiohsse constructive
Coherence?
Refers to waves having CONSTANR PHASE DIFFERENCE, and thus must have the SAME frequency, phase difference doesn’t have to be same but just constsnt , so thst intefecenc elatterms produced or stable
Pld/ wavelen5j x 2pi = phase difference
Here for every 1/2 lambda out, tout of hose,e lambda in lapse etc , from central order 0, we’re there is no path length difference
How does young double slit work
Well must come from same route so phase difference is constsnt, gets diffracted through double slit so two sources are produced and they interfere forming patterns
Stationary wage
This is where two progressive waves of same frequency travelling in opposite direction supoerpose, where they meet in anti phase destruct to for, w node , where they meet in phase construct to form Antonines
Nice disoslcment always 0
Speewgion between nodes is walkways half thr wwvelenthh
No net energy transfer
Difference s
STAIONARY produce no energy net, progressive does
Phase difference is thr swme between the nodes , oppsote side is antiphase
Wwvelenthh is half
Amplitude between all point sin stagikanry same but in stationary maximum at anti etc
Sting harmonics
I’d plug then that causes two oroeesive waves of same frewuencyn ti Tavel on each end reflex 190 and thus they supoerpose wnd form a dtaginwry wave
Funds,ent frequency is minimum frewuencyn needed
Which is fixed for given tensions etc v = f x WL
Node one shc side
One node and anti node
Will be odd
Both anti ode, = even
Here it will be internet r,it,impels, so double the frequency half length
Odd because always have to add 2/2 extra
Can work out by counting total wwvelenthh equation to L
Photoelectric effect
Shine photos on metal, providing above work function, electrons will emit
So on gold leaf this causes a positive charge to build up and they repel
Electrons only emitiredp
1) if incident radiation was above threshold frequency ,so if you increase intensity it wouldn’t increase or even let any electrons be released, which was shocking as original model was that waves were a clot lie bea, of energy
2) last threshold increases intensity, you increase e number if electrons emitted in one to ine tinetevtiodn
Increasing rsdisiton Abbie frequency less to electrons releasing with. Or energy
Einstein’s
Saudi electron needed a certain amount of energy needed to escape = to the work function , which was the minimum amount of energy needed to escape
So if frequency too low, then it would be be able to escape
Intersections anooen in one to one
Work function means not necaseilly all electrons escape will be from extra energy out in, because some may have higher energies, but this is minimum, so surfsce one’s theoretically should escapement
Hf = work + ke max
Max ke becuse e not be easily all will have thid energy
Do it sticks witjnjsutnwork function , no energy elft, so
So with graph as all rgwduenr same, based in different ttheshiod energies which is x intercept will be trnslsgwe
Wave particlmdusliru
Shoes all particles have abe and particle properties
Electrons can be diffracted, with dr brig lei wavkentgh = h / momentum
Electron wwvelenthh so small so very small selection enered that’s why pilyhcrstslien go white between atoms used
Here electron gun to split, and then they diffract and interfere to produce a pattern like waves
