if you put weak with W^+/- is that wrong?

I think there are some questions missing and am unsure about the resistance of the tin for the resistivity one.

**AS Physics Unit 1 Mark Scheme**

1a)K+=US bar(sorry can’t do bar symbol) because strangeness=1 therefore anti strange quark and charge is 1 so up’s charge of 2/3 is required to add with 1/3 charge of anti-strange to make 1 full charge.(not required) (1)

1b)Baryon Number=0 because it’s not a baryon or baryon number=1/3-1/3=0(not required) (1)

1c)K- because charge is opposite for antiparticle(not required).(1)

1d)beta minus decay electron/beta minus 0 -1 and antineutrino and 26,7 I think either way it was the element given plus 1 on the proton number and the same neutron number.

1e)K- to anti muon + muon neutrino

K- is a hadron,meson and is charged.

Anti muon is charged, isn’t a meson or hadron.

Muon Neutrino isn’t charged, isn’t a meson or a hadron.(3)

1f)Particle X is a neutral pion so that baryon number,lepton number and charge are conserved(not required).(1)

1g)Either baryon number, charge or lepton number conserved.(1)

2a)Q has the least protons(5) compared to 6,6 and 8.(1)

2b)P and R are isotopes due to having same number of protons.(2)

2c)atom with lowest proportion of charged particles(protons) to mass(protons and neutrons)(nucleon number).P I think can’t remember.(6 protons,14 nucleons) (2)

2d)strong nuclear force is repulsive up to 0.5-1.0 femtometres then it becomes an attractive force decreasing with distance separated between proton and neutron up to 0 at the range of strong nuclear force(3-4 femtometres).Graph would be good idea straight line down at 0.5-1.0 from repulsion to attraction and then it curves up to 3-4fm.(3)

2e) Weak Interaction exchange particle(Weak Boson W+ or W- or Z0) {EDIT:Looks like it is the Electromagnetic Force with exchange particle Virtual Photon I'm not sure of the question though that would help)(2)

3a) Interference with Double Slits has been observed with electrons.(1)

3b) wavelength=h/mv=6.63*10^-34/(9.11*10^-31*2.5*10^5)=2.9*10^-9 m(2sf)(3)

3c) velocity=h/(wavelength*mass)=1.2*10^3 ms^-1 (2)

3d) C=fwavelength frequency=3*10^8/(254*10^-9)=1.2*10^15 Hz(2)

3e) E=hf=6.63*10^-34*1.2*10^15=7.9*10^-19J =7.8*10^-19j=7.8*10^-19/(1.6*10^-19)ev=4.9ev(2)

4a)Ultraviolet Photons are emitted by mercury atoms(1).

4b) excited is where electrons in the mercury atom receive enough energy to move up energy levels.(2)

4c)electrons flow from either end of metal plates and collide with mercury atoms transferring their energy givi ng electrons enough energy to move to the next energy level.(2)

4d)The Excited electrons can then lose a varying amount of energy and drop different amounts of energy levels as they dexcite and because the difference between energy levels refers to the energy of the photomn released then different energy photons can be released and because photon energy is dependent on its frequency e=hf then differing frequencies can be produced.(3)

4e) Ultraviolet photons are incident on the fluorescent tube exciting the electrons in the flourscent tube as they receive enough energy to move to the next energy level and then they lose energy dropping energy levels as the dexcite and the difference between energy levels is the energy of visible light so visible light is emitted(2)

5a)Resistivity is the constant of proportionality of the directly proportional relationship of resistance and the ratio of length and cross sectional area for a specific material providing temperature remains constant.Resitivity is the product of resistance and the ratio of cross sectional area and length.(2)

5b)The Critical Temperature is the temperature at which below this a material becomes a superconductor and has zero resistance and it is significant because of this and that a material with a higher critical temeperature would be more useful.(2)

5c) P=RA/L=0.80*(0.5*10^-3)^2*pi/4.8=1.3*10^-7ohmmetre(unit required)-I’m not sure if it was 0.80 ohm resistance though.(2)

6a)The power is directly proportional at first(straight line) increasing as resistance increasing between 0.5-3 ohm up to a maximum of 3.0 watts but after this it has an inversely proportional relationship decreasing as resistance increases.(use figures)(2)

6b) at resistance 0.8 ohm power=1.9 p=i^2 sqrt(p/r)=i=sqrt(1.9/0.8)=1.5 amps (2)

Current=1.5 amps

6c) voltage=1.2 volts v=ir=1.5*0.8=1.2 volts (2)

6d) internal resistance=3.2 ohm emf=v+Ir (emf-v)/I=r=(6-1.2)/1.5=3.2 ohm (2)

6e) without internal resistance then the terminal voltage=emf and thus the equation P=V^2/R would work for the whole circuit therefore power would have an inverse relationship with resistance decreasing as resistance increased.(2)

7a) you would measure voltage/pd with a voltmeter and temperature with a thermometer. Heat thermistor with water bath(7 different readings between 0 and 100).R is required because otherwise voltmeter reading would equal emf and not change due to r as temperature increases and the resistance of the thermistor drops it will receive less potential difference due to having a resistance lower in proportion to R therefore the voltmeter reading will drop.Set up the experiment again and measure the potential difference across thermistor in room and compare with graph(I drew curved falling curve of voltmeter reading against temperature and indicated lines drawn to find out the temperature if you know the voltmeter reading.(6)

7b) If the voltmeter is connected across R then as the resistance of the thermistor decreases due to temperature increasing its resistance will be greater in proportion to the resistance of the thermistor so the reading on the voltmeter would increase.(3)

I think the paper was generally easy and whether or not some of us may have misread a question and put weak instead of electromagnetic it was a nice paper a decent bit harder than last year though so I would say A-54 B-47 C-39 D-32 E-26 with 100% UMS at 68/70

Ohh noo, I wrote electroSTATIC force with a photon for the exchange particle. Would I still get the marks?

what were the total marks for electricoty question?

Please tell me the answer for that question on electrons having a wave-like nature was 'diffraction'. PLEASE.

No oscilloscope questions ia ssumed there would be some because our isas wwre based on resisitivity

In question 2 which nuclei had the lowest specific charge and why?

Also I can't remember which question but explain the shape of the graph between 0.5-6.5 ohms?

whats been the highest ever raw mark for an A?