AQA Physics Unit 1 PHYA1 20th May 2014 OFFICIAL

has anyone done the june 2011 paper?
question 1 bii is bugging me
there are two decays
K+ -> pi+ +pi0
and
K+ -> mu+ + antimuon neutrino

the question asks which is impossible
and the markscheme says the second because lepton no. is not conserved
but it is isnt it
im reallly confused any help would be appreciated

Reply 121

hellomotto27

For specific charge calculations, do you include the mass of any electrons?
The rule seems to have changed in different past papers. Thanks!

Reply 122

__Adam__

9

Original post by hellomotto27

For specific charge calculations, do you include the mass of any electrons?
The rule seems to have changed in different past papers. Thanks!

If it says specific charge of the nucleus, ignore electrons. If it asks about an ion/atom, then include the electrons.

Reply 123

Usey11

Original post by rhiam

has anyone done the june 2011 paper?
question 1 bii is bugging me
there are two decays
K+ -> pi+ +pi0
and
K+ -> mu+ + antimuon neutrino

the question asks which is impossible
and the markscheme says the second because lepton no. is not conserved
but it is isnt it
im reallly confused any help would be appreciated

It isn't conserved as a mu+ is a antimuon (muon has a -1 charge) so LHS lepton number = 0 RHS leptop number = -2

Reply 124

rhiam

1

Original post by Usey11

It isn't conserved as a mu+ is a antimuon (muon has a -1 charge) so LHS lepton number = 0 RHS leptop number = -2

thank you so much :smile:

Reply 125

hellomotto27

Original post by __Adam__

If it says specific charge of the nucleus, ignore electrons. If it asks about an ion/atom, then include the electrons.

Thank you!

Reply 126

Venom193

1

Original post by Abby_W31

Not good, we did a mock last week in class and I got a U D: I'm absolutely s**ting it! Just gone through my notes and made three double sided revision pages that sum it all up, I hope I do better.

Just excuse me a minute while I go and cry in a corner!

Yeah, like I was just saying there ^ I got a U in my mock, why? Because it was largely electricity!

I just about scraped an E for the exact same reason!

Hopefully it will be more particle based.

Reply 127

__Adam__

9

Original post by rhiam

has anyone done the june 2011 paper?
question 1 bii is bugging me
there are two decays
K+ -> pi+ +pi0
and
K+ -> mu+ + antimuon neutrino

the question asks which is impossible
and the markscheme says the second because lepton no. is not conserved
but it is isnt it
im reallly confused any help would be appreciated

I think a muon is negatively charged like an electron, so mu+ would be an antiparticle therefore you're making 2 antiparticles in the second reaction, lepton number = -2

Reply 128

you-only-live-once

2

when calculating specific charge, do you have to separate proton and neutrons' mass? or can u use both at 1.67 x 10^-27?

Reply 129

Usey11

Original post by you-only-live-once

when calculating specific charge, do you have to separate proton and neutrons' mass? or can u use both at 1.67 x 10^-27?

You can use them together.

Reply 130

corsilo96

Do you need to know much about diodes? All we have been taught is the I/V characteristics.

Reply 131

toddmcnugget

7

A prediction on what an A grade is in ums for both papers and the practical?

Reply 132

NickyRF

Original post by corsilo96

Do you need to know much about diodes? All we have been taught is the I/V characteristics.

Nope. As long as you know the IV characteristics for the bulb, the diode, the wire and the thermistor you're sorted.

Reply 133

__Adam__

9

Original post by corsilo96

Do you need to know much about diodes? All we have been taught is the I/V characteristics.

Looking at the textbook, diodes only have a couple of paragraphs written about them. V/I graph and characteristics are pretty much it.

Original post by toddmcnugget

A prediction on what an A grade is in ums for both papers and the practical?

A is always 80% UMS (240/300) How many marks that is depends on how hard the paper is.

Reply 134

toddmcnugget

7

Original post by __Adam__

A is always 80% UMS (240/300) How many marks that is depends on how hard the paper is.

Jeez, I'm going to mess up tomorrow's paper (pretty sure) but hopefully I'll get full UMS in paper 2...

Reply 135

NickyRF

Hey, A2 student doing Unit 1 this year, due to family issues last summer. Have my head round Unit 1 pretty well and am happy to help this evening for anyone stuck on last bits. Send me a message.

Reply 136

zerock

4

It seems like im the only one in my class who finds paper 1 harder than paper 2 :s-smilie:

Reply 137

__Adam__

9

Original post by toddmcnugget

Jeez, I'm going to mess up tomorrow's paper (pretty sure) but hopefully I'll get full UMS in paper 2...

Just had a look on the raw/ums bit of the aqa site, an A is roughly 55/56 marks. As I said, it varies a bit between tests, but it seems to be in that general area.

(edited 9 years ago)

Reply 138

toddmcnugget

7

Original post by __Adam__

Just had a look on the raw/ums bit of the aqa site, an A is roughly 55/56 marks

That's not too bad I guess, good luck to all!

Reply 139

Maricamac

can I just ask how do we work out specific charge, I always get it wrong.
Usually i put electron charge x no of electrons over the (electron mass x electron no) x (neutron mass x neutron number)

AQA Physics Unit 1 PHYA1 20th May 2014 OFFICIAL

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