Biology; Chemistry; Physics: Post your doubts here!

[smiling star]

Germination of seeds

-Definition
Development of seed into a new plant when conditions are favorable
Conditions required
Optimum temp for enzyme activity
Oxygen and water for respiration to make energy
-Dormant period

Resting period when they're dry and reduced activities so they can survive the unfavorable conditions
-Stages of germination be it epigeal orhypogeal

Absorption of water causes the seed to swell
Food stored converted to sugars
So seed respires to release energy
Energy used for growth
As a result radicle emerges followed by plumule
On the development of cotyledon photosynthesis starts since they are green and thus the seedling now becomes a self supporting plant

If cotyledons below earth so hypo and if above so epigeal germination

Hope this helps out, remember me in your prayers, Jazak Allah!:')

 

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Can someone explain role of fermenter in biotechnology btw?

 

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Can someone post a link or any worksheet or anywhere I can practise moles from other than chem pastpapers?
Thankyouu

 

[mistique_bee]

Can someone explain role of fermenter in biotechnology btw?

My Name

 

[mistique_bee]

Can someone post a link or any worksheet or anywhere I can practise moles from other than chem pastpapers?
Thankyouu

https://www.xtremepapers.com/community/threads/amazing-notes-on-chem.32028/#post-719654
U cn find it here...

 

[My Name]

My Name

I actually dont remember fully. :/
Take a look here :http://michellebiology.blogspot.com/2012/02/58-fermenter.html
and fro rveision check this:http://igbiologyy.blogspot.com/2012/12/25-use-of-microorganisms-and-fermenter.html
hope that helps

 

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Thankyou so much both :')

 

[smiling star]

Also, cathode ray oscilloscope and the entire chapter of electronics is a nightmare and with just a month left idk how to study this chapter

 

[darkvoid]

Also, cathode ray oscilloscope and the entire chapter of electronics is a nightmare and with just a month left idk how to study this chapter

There isn't much in electronics really. You aren't doing digital logic circuits , are you? cause its optional.
Basically just know resistors, little bit of diode (allows current to flow in one direction only) , light emitting diode (LED emits light + diode function) and capacitor (stores charge and is thus used in time delay circuits). There is one important question for capacitor , I don't remember which year but it was variant 21. It was difficult.

CRO just consists of a number of components:
1) electron gun - has a filament connected to a power supply. The filament heats up emitting electrons due to thermionic emission. An anode in front attracts the electrons and helps them to speed up.
2)Deflecting plates - There are two, voltage can be applied to deflect electrons. X-plates are used to control the electron beam's horizontal deflection and Y-plates are used to control vertical deflection.
3)Fluorescent screen - coated with a salt which lights up when hit by electrons.

CRO can be used to measure voltage. Connect the wires to Y-input terminal and observe the trace formed on the screen.
Timebase can be adjusted to make the trace formed wider or shorter.
When it is off a single spot will be seen on the screen. The spot moves up when a positive voltage is applied and down when a negative voltage is applied. Turning on the time base makes the spot turn into a horizontal line. If an ac current is applied a wave will be formed when time-base is on.

Just do maximum pastpaper questions and you'll be fine.
Good Luck!

 

[smiling star]

There isn't much in electronics really. You aren't doing digital logic circuits , are you? cause its optional.
Basically just know resistors, little bit of diode (allows current to flow in one direction only) , light emitting diode (LED emits light + diode function) and capacitor (stores charge and is thus used in time delay circuits). There is one important question for capacitor , I don't remember which year but it was variant 21. It was difficult.

CRO just consists of a number of components:
1) electron gun - has a filament connected to a power supply. The filament heats up emitting electrons due to thermionic emission. An anode in front attracts the electrons and helps them to speed up.
2)Deflecting plates - There are two, voltage can be applied to deflect electrons. X-plates are used to control the electron beam's horizontal deflection and Y-plates are used to control vertical deflection.
3)Fluorescent screen - coated with a salt which lights up when hit by electrons.

CRO can be used to measure voltage. Connect the wires to Y-input terminal and observe the trace formed on the screen.
Timebase can be adjusted to make the trace formed wider or shorter.
When it is off a single spot will be seen on the screen. The spot moves up when a positive voltage is applied and down when a negative voltage is applied. Turning on the time base makes the spot turn into a horizontal line. If an ac current is applied a wave will be formed when time-base is on.

Just do maximum pastpaper questions and you'll be fine.
Good Luck!

Thankyouu so muchh:'))
This was surely helpful and consoling:')
No no I'm leaving the optional section out
I know diodes resistor and LED
And after this post CRO sounds simple too, thankss;'))
Can you elaborate transistor and capacitor the same way too please, I'd be thankful and goodluck to youu too!

 

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Please anyone can you solve this one ASAP!thanks

 

[Error Syntax]

Its a D. Working : Use formula Temp=(L@-L0/l100-l0)x Range and if you are confused by this see it in your book under the topic of temperature.
Then we have to identify the variables L0=2 and l100=22 and if we apply the formula it looks like this

 

[smiling star]

Its a D. Working : Use formula Temp=(L@-L0/l100-l0)x Range and if you are confused by this see it in your book under the topic of temperature.
Then we have to identify the variables L0=2 and l100=22 and if we apply the formula it looks like this

Oh so that's how it's done, thanks a bunch bro
Can you guide me a bit in physics though?

 

[darkvoid]

Thankyouu so muchh:'))
This was surely helpful and consoling:')
No no I'm leaving the optional section out
I know diodes resistor and LED
And after this post CRO sounds simple too, thankss;'))
Can you elaborate transistor and capacitor the same way too please, I'd be thankful and goodluck to youu too!

Sorry for the late reply , I'm not really that active on these forums.
Transistors (as far as I know) are not included in our syllabus.
For capacitors , I don't know too much but I can tell a little on what I know.
Generally capacitors are used in time delay circuits as mentioned before. Especially in household alarms. The alarm is switched on and the capacitor starts storing charge. This causes a time delay since the alarm doesn't go off until the capacitor is fully charged and then discharged. The delay allows the house keeper to leave the house in time before the alarm gets activated.
When the circuit switch is closed , the potential difference across the capacitor increases slowly, the capacitor charges at a decreasing rate to a maximum value. It is then ready to sound the alarm when it is triggered by discharging.

Hope this helps, if anyone has extra info please add it since I also want to know more about this topic.
Good Luck!

 

[Error Syntax]

Oh so that's how it's done, thanks a bunch bro
Can you guide me a bit in physics though?

Yeah sure I was doing the same paper when you posted that question.

 

[smiling star]

Sorry for the late reply , I'm not really that active on these forums.
Transistors (as far as I know) are not included in our syllabus.
For capacitors , I don't know too much but I can tell a little on what I know.
Generally capacitors are used in time delay circuits as mentioned before. Especially in household alarms. The alarm is switched on and the capacitor starts storing charge. This causes a time delay since the alarm doesn't go off until the capacitor is fully charged and then discharged. The delay allows the house keeper to leave the house in time before the alarm gets activated.
When the circuit switch is closed , the potential difference across the capacitor increases slowly, the capacitor charges at a decreasing rate to a maximum value. It is then ready to sound the alarm when it is triggered by discharging.

Hope this helps, if anyone has extra info please add it since I also want to know more about this topic.
Good Luck!

Alright thankyouu :')
What exactly are time delay circuits though?
Are you appearing this year too for phys?

 

[darkvoid]

Alright thankyouu :')
What exactly are time delay circuits though?
Are you appearing this year too for phys?

Circuits in which there is a delay, before current starts flowing, like the alarm you don't want it to go off immediately after setting it when you still haven't left your house.
Yeah appearing for May/June 2016 English,Math D, Physics , Chem,Bio

 

[smiling star]

Circuits in which there is a delay, before current starts flowing, like the alarm you don't want it to go off immediately after setting it when you still haven't left your house.
Yeah appearing for May/June 2016 English,Math D, Physics , Chem,Bio

Oh thanks I find capacitors easy now Alhamdulillah :')
Samee here
So how are you revising in April
Everyone's telling me to stick to pastpapers but there are topics that I need to further strengthen and with just less than a month left :/

 

[darkvoid]

Oh thanks I find capacitors easy now Alhamdulillah :')
Samee here
So how are you revising in April
Everyone's telling me to stick to pastpapers but there are topics that I need to further strengthen and with just less than a month left :/

Well, I am done with all pastpapers from 2005 - 2015 for Sciences. Currently I'm doing Maths 2015 papers. I guess I will focus on English now and read topics again from the book especially for Bio. It is best to switch to the book now if you are done with pastpapers.

 

[smiling star]

Well, I am done with all pastpapers from 2005 - 2015 for Sciences. Currently I'm doing Maths 2015 papers. I guess I will focus on English now and read topics again from the book especially for Bio. It is best to switch to the book now if you are done with pastpapers.

Ohh well its quite the opposite for me
Are you done with all pastpapers including Atps?
I'm done with bio books and notes just left with one chapter of drugs and I've done somewhat topical pp I'll now start yearly pastpapers from 2015 and go backwards
Will do same in every subject as in phys and chem
And I need to do atps too but I'll do atps when I'm done with my theories atleast 5 years
As for math addmath I've been doing topical pastpapers but I'll start yearly from today
I'm worried for English though, Idk how to study for that