AQA Physics Unit 1 PHYA1 20th May 2013

thanks a lot.

would really appreciate it if someone has a list of units they can share (mega, milli) and their conversions? thanks

Gev = 1000Mev = 1000 000 000 ev Just read this one in the text book now :smile:

1A = 1000mA

1k(ohm) = 1000 ohm

Reply 221

x-Sophie-x

13

Original post by BenChard

thanks a lot.

would really appreciate it if someone has a list of units they can share (mega, milli) and their conversions? thanks

(Someone help me out here!) Giga?! = 10^9
Mega=10^6
Kilo=10^3
Milli=10^-3
Micro=10^-6
Nano^-9

1ev=1.6x10^-19
1Mev=1.6 x-13

(edited 10 years ago)

Reply 222

posthumus

20

Original post by x-Sophie-x

(Someone help me out here!) Giga?! = 10^9
Mega=10x^6
Kilo=10^3
Milli=10^-3
Micro=10^-6
Nano^-9

Correct !

Reply 223

Substitution

3

Original post by posthumus

I don't know if I have a good way of remember....

but I remember them because of computer memory kilobytes is 1000 bytes (or km is 1000m) mega is 10⁶ giga 10⁹ and you must have heard of tera- as well 10¹².. but to be fair you probably won't come across that :smile:

milli is 10^-3 (think of how many millimeters there are in a meter - 10 in 1cm & 100cm in 1m... therefore 1000mm in 1 meter)

micro is 10^-6

nano is 10^-9

Some calculators can convert units for you such as the fx--991ES, but I don't think you should have problems remember these powers :smile:

that's really helpful, I do have that calculator but it can only convert between different units like cm to inches thanks though

Reply 224

Jimmy20002012

4

Could we get a circuit question with diodes in them?

Posted from TSR Mobile

Reply 225

Xiomara

18

Original post by posthumus

Ah yes the 6 markers are such a pain, I prefer it when the 6 marker is applying theory (like in unit 4) otherwise it's pointless :smile:

I haven't started preparing for unit 1 yet (I know... lol -_-) but I will probably focus on the potential six marker over the weekend, so I'll send you any bullet points I do make :smile:

But revision guides usually do have the bullet points of pretty much all experiments you should know about...?

Thank you!
Yes, I've been using the CGP revision guide, it's actually pretty good. For some reason I just seem to struggle with them!

_{Original post by Jimmy20002012Could we get a circuit question with diodes in them?

Posted from TSR Mobile

Do the specimen paper on the AQA website, they come up}:/

Reply 226

Son234

Original post by Xiomara

Thank you!
Yes, I've been using the CGP revision guide, it's actually pretty good. For some reason I just seem to struggle with them!

_{Do the specimen paper on the AQA website, they come up}:/

I'm using the CGP book what do you think of the jokes?

Just a off topic question :smile:

This was posted from The Student Room's iPhone/iPad App

Reply 227

sceezy

hey, does anyone have like a list of possible 6 markers??? :s. Or even any tips on revising them?

Reply 228

ak395

6

Original post by sceezy

hey, does anyone have like a list of possible 6 markers??? :s. Or even any tips on revising them?

Look at the markschemes and learn them

I'll probably copy and paste them all off the markschemes tonight and i'll post on here when I'm done. Also, they're all pretty similar so if you do a few you'll get the hang of them. There's the ones where you have to plot the I-V graphs, or change the temperature of a thermistor and work out the resistance, or the photoelectric effect, excitation and de-excitation, fluorescent lamps, how to find out if the rms values and frequency of a power supply is accurate using an oscilloscope.

I think they're the ones I've come across so far.

(edited 10 years ago)

Reply 229

Xiomara

18

Original post by Son234

I'm using the CGP book what do you think of the jokes?

Just a off topic question :smile:

This was posted from The Student Room's iPhone/iPad App

I'm a sucker for cheesy things like that, I quite like them! ;p You?

Reply 230

StalkeR47

5

Original post by Jimmy20002012

Could we get a circuit question with diodes in them?

Posted from TSR Mobile

Hello Jimmy! Do you remember me? Yes you can get a diode question. But it is not hard at all! A single diode (only allows current to flow through in 1 direction) requires 0.6V to let the voltage in the battery pass through to the rest of the components.

Reply 231

Jimmy20002012

4

Original post by StalkeR47

Hello Jimmy! Do you remember me? Yes you can get a diode question. But it is not hard at all! A single diode (only allows current to flow through in 1 direction) requires 0.6V to let the voltage in the battery pass through to the rest of the components.

Yeah how could I forget you :wink:

. What happens if you have a reverse diode, isn't it that no current would flow. Also if you has a reversed diode and a bulb in parallel with another bulb, the bulb would not switch on because no current would flow am I right? but what would be the voltage for that diode and bulb? and would the current for the other bulb be at maximum as there would not be any current flowing through the bulb and diode???

Posted from TSR Mobile

Reply 232

Didierr

How do you reverse a current to see the result in the third quadrant of a graph?
Is a reversed current just a negative current?

Reply 233

Me123456789

21

Original post by posthumus

http://www.youtube.com/watch?v=U0kXkWXSXRA

Original post by x-Sophie-x

For the quark combinations of pions and kaons, my teacher suggested 'don't stand under dark umbrellas' :smile:

Not sure if that will be any help but hey xD

I don't know of anything else :redface:

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Thanks.

Reply 234

Goods

16

Original post by Didierr

How do you reverse a current to see the result in the third quadrant of a graph?
Is a reversed current just a negative current?

you swap the orientation of the component or biased direction for a diode or change the battery terminals around

Reply 235

Anujan Murugesu

Original post by BenChard

that's really helpful, I do have that calculator but it can only convert between different units like cm to inches thanks though

The fx 991 ms can convert these units. Shift + 9,7,6

Reply 236

IWantSomeMushu

17

Original post by StalkeR47

Thanks! But older past papers than 2009 have radiation in them instead of electricity. :frown:

What do you mean? The old spec PHA3/W papers are called Current Electricity and Elastic Properties of Solids.

Reply 237

StalkeR47

5

Original post by Jimmy20002012

Yeah how could I forget you :wink:

. What happens if you have a reverse diode, isn't it that no current would flow. Also if you has a reversed diode and a bulb in parallel with another bulb, the bulb would not switch on because no current would flow am I right? but what would be the voltage for that diode and bulb? and would the current for the other bulb be at maximum as there would not be any current flowing through the bulb and diode???

Posted from TSR Mobile

Yes m8 you are right! The diode would be reversed bias so the current in the circuit would be negligible. Let's assume we have a 9V battery and it is connected with a diode in it's 'forward bias' and with a filament bulb. You can easily determine the voltage at the bulb which would be 8.4V. This is because the diode requires 0.6V to let voltage pass through so 9-0.6=8.4V. As I said if the diode is reversed bias, the voltage cannot pass through the diode since it wont allow any current to pass through. And therefore, the bulb will not glow...

Reply 238

Jimmy20002012

4

Original post by StalkeR47

Yes m8 you are right! The diode would be reversed bias so the current in the circuit would be negligible. Let's assume we have a 9V battery and it is connected with a diode in it's 'forward bias' and with a filament bulb. You can easily determine the voltage at the bulb which would be 8.4V. This is because the diode requires 0.6V to let voltage pass through so 9-0.6=8.4V. As I said if the diode is reversed bias, the voltage cannot pass through the diode since it wont allow any current to pass through. And therefore, the bulb will not glow...

What about a resistor would voltage go through that if diode is reversed? :smile:

Posted from TSR Mobile

Reply 239

StalkeR47

5

Original post by Jimmy20002012

Yeah how could I forget you :wink:

. What happens if you have a reverse diode, isn't it that no current would flow. Also if you has a reversed diode and a bulb in parallel with another bulb, the bulb would not switch on because no current would flow am I right? but what would be the voltage for that diode and bulb? and would the current for the other bulb be at maximum as there would not be any current flowing through the bulb and diode???

Posted from TSR Mobile

Hey Jimmy! I think you re still a bit confused. Let me clear that...... Consider a forward diode with a bulb and a battery with a conventional current towards the flat end of the diode. (try to sketch this), now the bulb will be on. Draw a same diagram with the conventional current towards the pointed edge of the diode, the bulb will be off because there will be no current. This is the state in which the polarity is reversed compared to you first diagram and therefore, for the voltage, the diode is reversed bias. Got it?

AQA Physics Unit 1 PHYA1 20th May 2013

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