National 5 Physics 2018-19

Just me that knows my electricity notes off by heart but has no clue how to any of the questions relating to circuits? I'm perfectly confident with everything else, but I feel like I will be let down due to electricity, because I just have no idea how to answer them.

Reply 22

rittajmoghal29

10

Original post by Strelzo

Just me that knows my electricity notes off by heart but has no clue how to any of the questions relating to circuits? I'm perfectly confident with everything else, but I feel like I will be let down due to electricity, because I just have no idea how to answer them.

I understand, it's like sometimes I get my answers correct but in tests or past papers it ends up wrong.
Don't worry too much about it as long as you know your resistance formulas. Is it the resistance bit you are struggling with or mixed circuits with Voltage and finding the overall current?

Reply 23

username4557616

4

I got 68% in my prelim and I'm aiming for an A in my exam so I was a little disappointed. Any tips for revising before the exam

Reply 24

elenitzemos

4

Actually, usually the grade boundary for a A is 68%. The SQA like to have approx 30% of candidates achieve an A and it just so happens that in recent years, that's lowered the A grade to 68%. I was having the exact same struggle- but remember that no matter what happens in the exam you still have your assignment which can sometimes boost your grade significantly xx

Original post by Crazymuffineater

I got 68% in my prelim and I'm aiming for an A in my exam so I was a little disappointed. Any tips for revising before the exam

Reply 25

username4557616

4

Thanks, that's made me feel a bit better 🙂

Reply 26

Original post by rittajmoghal29

I understand, it's like sometimes I get my answers correct but in tests or past papers it ends up wrong.
Don't worry too much about it as long as you know your resistance formulas. Is it the resistance bit you are struggling with or mixed circuits with Voltage and finding the overall current?

It's the really awkward mixed circuits that include transistor's/mosfet's/led's, etc. I scheduled a date to go over some things with my teacher regarding electricity, and it cleared things up, I'd say I'm 70/30 now, but shouldn't matter to much as long as I study my other stuff.

Reply 27

Vladimir Poutine

13

I was finding the transistor ones difficult too and these are the notes I took that cleared it up for me, in case they might be of use to somebody out there.

Original post by Strelzo

It's the really awkward mixed circuits that include transistor's/mosfet's/led's, etc. I scheduled a date to go over some things with my teacher regarding electricity, and it cleared things up, I'd say I'm 70/30 now, but shouldn't matter to much as long as I study my other stuff.

Reply 28

Original post by Vladimir Poutine

I was finding the transistor ones difficult too and these are the notes I took that cleared it up for me, in case they might be of use to somebody out there.

Yep, they are the questions that are a pain lol. I know notes off of the top of my head, just trying to answer a question doesn't come as clear to me as it does others. So thanks for your help :smile:

Reply 29

The thing that also messed me up I'd say is one of my teachers, we have this really good teacher, and this really crappy one. The good teacher explains everything in great detail and is the one who I went for help, the crappy one went into higher and got my notes to be all over the place and to not make sense.

Original post by Strelzo

Yep, they are the questions that are a pain lol. I know notes off of the top of my head, just trying to answer a question doesn't come as clear to me as it does others. So thanks for your help :smile:

Reply 30

Vladimir Poutine

13

I know right? Electricity ones are just difficult and boring.

Original post by Strelzo

Yep, they are the questions that are a pain lol.

Reply 31

tomctutor

Original post by Vladimir Poutine

I was finding the transistor ones difficult too and these are the notes I took that cleared it up for me, in case they might be of use to somebody out there.

Good notes, if the active resistor (the LDR, Thermistor etc) is in the lower leg of the Voltage Divider then the transistor will switch on when the (Light level, temperature etc) is Low- or a low level sensor circuit. Once the transistor switches on, current flows through the lamp which will illuminate (on) , also sometimes a relay is used here to provide for high-voltage output.
Conversely if the active resistor is in the upper leg then the transistor will switch on when the light level, temperature etc, is high.
A BJT or Bipolar Junction Transistor has base-emitter-collector as in above image (SQA just use npn types as switches, not amplifier dont worry about Hfe).
Learn what a MOSFET is and remember where the gate, source and drain are on the symbol ( a mosfet switches on with gate voltage

2volt

.
A thermistor, LDR etc are semiconductor devices- these don't obey Ohms Law (i.e. they don't have fixed resistance). Ohms Law can be written as

V=IR

(edited 4 years ago)

Reply 32

beth1709

How is everyone feeling for the exam? What do you all find the hardest? Just curious to see if it’s the same as what I think.

Reply 33

Original post by beth1709

How is everyone feeling for the exam? What do you all find the hardest? Just curious to see if it’s the same as what I think.

Everything is pretty easy; then there's electricity - nightmare electrical circuit questions.

(edited 4 years ago)

Reply 34

zras83

Original post by beth1709

How is everyone feeling for the exam? What do you all find the hardest? Just curious to see if it’s the same as what I think.

I’m really nervous since physics isn’t a very strong subject for me. I find electricity quite difficult - one minute i think i understand it, but then i get a question that makes no sense to what i’ve just learned which can be very frustrating. I’m gonna work hard though for the next couple of days so that I can get a good grade. The annoying thing is that i’ve got history on Monday and French on Tuesday, so i’ll be exhausted for physics on wednesday but fingers crossed that it’ll be ok ahaha

Reply 35

Vladimir Poutine

13

Same here - really stressful weekend coming up for us lot!

Reply 36

Original post by Vladimir Poutine

Same here - really stressful weekend coming up for us lot!

Next week is going to be hell, starting on the 14th, I have French, 15th I have Physics and 16th I have Business Management in the morning and Design and Manufacture in the afternoon. However once I complete these, I'll only have Computing Science left to do and then I'm done.

Original post by Strelzo

Next week is going to be hell, starting on the 14th, I have French, 15th I have Physics and 16th I have Business Management in the morning and Design and Manufacture in the afternoon. However once I complete these, I'll only have Computing Science left to do and then I'm done.

That sounds horrendous!

Reply 38

beth1709

Yeah, I’m the exact same. Had English on Thursday, Chemistry today and then have French, Physics and History next week. I am so exhausted

Original post by zras83

I’m really nervous since physics isn’t a very strong subject for me. I find electricity quite difficult - one minute i think i understand it, but then i get a question that makes no sense to what i’ve just learned which can be very frustrating. I’m gonna work hard though for the next couple of days so that I can get a good grade. The annoying thing is that i’ve got history on Monday and French on Tuesday, so i’ll be exhausted for physics on wednesday but fingers crossed that it’ll be ok ahaha

Reply 39