1.
Significant figures.Do I always presume it’s the same as the SF of the values in the question? What about calculations do I use the rounded figure for these always? When there is no SF mentioned do I just take 2SF to be the standard?
1.
For a double slit experiment, why is it necessary that waves be coherent, Surely you can find certain non-coherent waves that can form an IP if they’re given the right WL. Secondly white light is composed of light of differing wavelengths, yet it would still show an IP, so coherence isn’t necessary here? There are differing definitions for coherence, some suggest it's CPD + frequency others CPD + wavelength, which is it?
2.
Exam question: Calculate FS by using a figure with a ruler below (with 25 maxima), I got 5.24mm which was correct, it then asks to determine diffraction spacing (Given WL as 628nm and DtS as 2.5m), using dsin(theta) = n x WL. Maybe I'm missing some understanding here but I get that sin(theta) = tan(theta) which = FS/DtS However in the answer they use FS as 0.13/2.5, where is this value from, I get it's 5.24mm x 25? But I feel like I'm missing something, why does n = 25? I get that's the number of maxima, but surely n would be 12 or 13 because the fringes are repeated on either side, and on the diagram there are 25 maxima but if I set n = 25 aren't I calculating 25 maxima on one side of the IP?
3.
Exam question: when a spectrometer is rotated from an initial angle of zero degrees a spectrum is first seen when the spectrometer is turned to 50 degrees. it asks you to determine the number of orders of the spectrum, how?! The next question states what is the difference in light emerging from the 50 degree point to the light emerging from the zero degree point? Then using dsin(theta) = n x Wlstyle question they set theta as 51 degrees, what is going on here?
4.
How does intensity varies as you increase the number of slits, Why for 1 slit is the central fringe 2x the size of the outer fringes? Why does i ntensity blend in 1 slit? why is WL/2 dark fringes for multiple slits and bright fringes for 1 slit
5.
What are orders of diffraction gratings? what is a zero-order maximum? Why set n as the number of fringes and not no of fringes/2 (as they are repeated)?
1.
I'm confused on Interactions and Decay differentiation. Exam question: a pion + proton = kaon +X (another strange particles), which interaction is involved here. I get strangeness separates WNF from SNF . The answer isSNF but what if the X was +1 strangeness. How can I just assume it’s -1?
2.
Why is a Neutron decay called a B- Decay, yet a Proton is termed stable when a B+ decay exists?Why do questions asking for Neutron decay only require B- Decay, aren’t there many ways it could decay? What separates decay and interaction in an equation?
3.
In Photoelectricity it is stated that the no of electrons emitted is proportional to the intensity of the light, but light intensity = no of photons/per sec and =energy of photons/per sec. Wouldn’t no of photons/per sec not change the rate of electron emission?
4.
For excitation the specification states it is an electron moving from a lower energy state to a higher energy state Isn’t this just one form of excitation? This is probably AS Scope but surely then it would be best to state: describe excitation in terms of electrons. Not just describe excitation?
1.
How does adding multiple resistors slow down the current at all points in the circuit.
2.
How and why is potential difference shared for components in parallel.
3.
Why is total emf the sum of potential drops around the circuit why does a charge flow, do some work one one comp and the rest of it on the other comp? why not vice versa? Why not do only the work required?
1.
Efficiency is written as useful energy/energy supplied. One question it states that an exercise bike pedals against a brake force of 30N at speed 15ms, I know P = Fv, but why isn't useful energy transferred the kinetic energy?
2.
How do I determine which is the input power and what is the output power, easy for say a bulb or a machine much harder for something organic.
1.
How does adding multiple resistors slow down the current at all points in the circuit.
2.
How and why is potential difference shared for components in parallel.
3.
Why is total emf the sum of potential drops around the circuit why does a charge flow, do some work one one comp and the rest of it on the other comp? why not vice versa? Why not do only the work required?