OCR Physics A G485 - Frontiers of Physics - 18th June 2015

Reply 920

sagar448

4

Original post by LilDurk

If that computing exam is f453, you ready?

Exam bord is AQA, sorry mate. :tongue:

Reply 921

The Room Student

2

Hey peeps! :smile:

1) what do you guys mean by a potential 'comet' question?

2) does anyone know which past paper that 'capacitor bullet' question came up on?

Reply 922

L'Evil Fish

OP

18

Original post by The Room Student

Hey peeps! :smile:

1) what do you guys mean by a potential 'comet' question?

2) does anyone know which past paper that 'capacitor bullet' question came up on?

Jan 13

Reply 923

jamesbird18

4

Original post by sagar448

No probs.

Yeah did do core 4 today, best paper I've had so far which is good. :biggrin:

DE? What do you mean DE? Kind of forgetful, remind me. :tongue:

Yeah I got K as 4. Loved that question! I know a lot of people would find that hard, but I found that question quite easy!

:biggrin:

Which exam board were you on?

Reply 924

ETRC

17

Original post by BecauseFP

Smoke alarm, mass spectrometer, comets, really hard fields question, alpha particle scattering,

what the fck can they ask about a smoke alarm?

do we need to know why it works?

i can't remember anything for this lol need to do so much revision in 1 day

Reply 925

sagar448

4

Original post by jamesbird18

Which exam board were you on?

Edexcel.

Reply 926

Username13

8

difference between homogeneous and isotropic?

Reply 927

Username13

8

Smoke alarm: (what i can remember)

Alpha radiation in smoke alarm allows a current to flow. Smoke particles come into the alarm and scatters the alpha radiation, current stops flowing and so the alarm goes off

Reply 928

Ayjayroo

1

Original post by ETRC

what the fck can they ask about a smoke alarm?

do we need to know why it works?

i can't remember anything for this lol need to do so much revision in 1 day

Americium - 241 emits Alpha particles

Alpha particles ionise the air in the alarm.

A current flows in the circuit.

When smoke enters the alarm, the charged particles stick to the smoke particles and the current in the circuit decreases.

When the current drops below a certain threshold, the alarm goes off.

Reply 929

sagar448

4

Original post by Username13

difference between homogeneous and isotropic?

Homogenous - same in all directions
isotropic - uniform density

Reply 930

L'Evil Fish

OP

18

Original post by sagar448

Homogenous - same in all directions
isotropic - uniform density

Other way around?

Reply 931

Elcor

14

Original post by Username13

Smoke alarm: (what i can remember)

Alpha radiation in smoke alarm allows a current to flow. Smoke particles come into the alarm and scatters the alpha radiation, current stops flowing and so the alarm goes off

Alpha particles ionise air which causes current to flow
Smoke particles adsorb alpha radiation so air is not ionised
Current stops which is detected and the alarm sounds

Original post by Username13

difference between homogeneous and isotropic?

Homogenous: content is the same throughout {?}
Isotropic: looks the same in all directions

Reply 932

sagar448

4

Original post by L'Evil Fish

Other way around?

Whoops, sorry. Yup, other way around.

Reply 933

ETRC

17

Original post by Ayjayroo

Americium - 241 emits Alpha particles

Alpha particles ionise the air in the alarm.

A current flows in the circuit.

When smoke enters the alarm, the charged particles stick to the smoke particles and the current in the circuit decreases.

When the current drops below a certain threshold, the alarm goes off.

thanks i knew the bottom 3 points just not what was used as the alpha source.

Reply 934

leroythelost

10

I don't want to annoy anyone but can someone motivate me to revise... tonight and not just tomorrow. This is my last exam..

Reply 935

L'Evil Fish

OP

18

Original post by leroythelost

I don't want to annoy anyone but can someone motivate me to revise... tonight and not just tomorrow. This is my last exam..

Nah, just work tomorrow!

Or watch some videos tonight

Reply 936

actanide

2

Original post by leroythelost

I don't want to annoy anyone but can someone motivate me to revise... tonight and not just tomorrow. This is my last exam..

Remember youre doing this for yourself. You didn't spend last two years in college/sixth just to not revise on the last two days and lose stupid marks because you didnt revise it.

On the other hand, maybe its better to take a day off today and just revise tomorrow, you usually cant force it

Reply 937

leroythelost

10

Original post by L'Evil Fish

Nah, just work tomorrow!

Or watch some videos tonight

I will feel guilty but on the other I am so not bothered as I already know I not going to get the grade I need for uni..

Reply 938

leroythelost

10

Original post by actanide

Remember youre doing this for yourself. You didn't spend last two years in college/sixth just to not revise on the last two days and lose stupid marks because you didnt revise it.

On the other hand, maybe its better to take a day off today and just revise tomorrow, you usually cant force it