IGCSE PHYSICS DOUBTS HERE !!!!

[HUSH1994]

New doubts,i hope anyone can help me,as from the IGCSE syallbus:
1.Describe compressions and rarefactions.
2.Give an account of charging by induction
3.Recall and use simple electron model to distinguish between conductors and insulators(easy things made hard :S )
4.What are relays and capacitors used for(other than storing energy)
5.Describe the action of a transistor as an electrically operated switch and show understanding of its use in switching circuits.
6.Recognize and show understanding of circuits operating as light sensitive switches and temperature operated alarms(using a relay or transistor)
7.Explain and use the terms analogue and digital.
and the whole 4.5 section except c.

Hope anyone can help,and thanks

[The Golden Girl =D]

New doubts,i hope anyone can help me,as from the IGCSE syallbus:
1.Describe compressions and rarefactions.
2.Give an account of charging by induction
3.Recall and use simple electron model to distinguish between conductors and insulators(easy things made hard :S )
4.What are relays and capacitors used for(other than storing energy)
5.Describe the action of a transistor as an electrically operated switch and show understanding of its use in switching circuits.
6.Recognize and show understanding of circuits operating as light sensitive switches and temperature operated alarms(using a relay or transistor)
7.Explain and use the terms analogue and digital.
and the whole 4.5 section except c.

Hope anyone can help,and thanks

I'll iA help u but i srsly gotta gimme sometime , k

[HUSH1994]

thanks golden girl,may i know which grade r u moving to

[The Golden Girl =D]

thanks golden girl,may i know which grade r u moving to

5alasit il IG Alhamdulilah ....O once  school starts ra7 koon an AS student iA

[HUSH1994]

5alasit il IG Alhamdulilah ....O once  school starts ra7 koon an AS student iA

same here

[The Golden Girl =D]

1.Describe compressions and rarefactions.

1.the only waves that have compressions and rarefactions are Sound Waves .

Compressions : is the region when particles  are closer than normal and are at a higher pressure than Normal.

Rarefactions : is the region where particles are farther from each other and are at a lower pressure than normal

this al the info i got

2.Give an account of charging by induction

1.it occurs due to the movement of free electrons of a conductor from one side to the other under effect of an outside charge . An Opposite Charge is always formed towards the charging body .Notice that no net changed is produced in the conductor ; when the charging body is removed , the conductor becomes uncharged .

O3indi hina 9oora ....fiha a Positively charged Rod foog ......Wi an Uncharged Body mithil a Paper ....

i.e lamma ana jubt il positively charged ROD jamb il Uncharged Object ..the Uncharged Object was attracted to the ROD ..fa the side next to the ROD had  electrons (-vely chrged) ...wil jiha ilba3eed min ilROD is positively Charged ....... if u wanna remove il positively charged u'll use smthn else called *EARTHING* ..ili huwa wire connected to earth wich will nuetralise il +vely charged side of the Paper .

I hope u got , it's simple ..don't worry

3.Recall and use simple electron model to distinguish between conductors and insulators(easy things made hard :S )

1. wallahi hadi madri ...Bas i remeber an Experiment from maybe 8th grade or smthn ...here it is :

3indi fi i9ura .....a Rod ..half of it is made of Wood and the other half is made of Brass *ili huwa a kind of metal* .......and there is a paper placed in the center makan ween they both materials  meet ... and then light a Bunzen Burner *Fire ..a mathc ..etc* under it ...and the paper above the brass doesn't Burn shwoin that it is a CONDUCTOR

Hope that helped :$

http://www.astarmathsandphysics.com/igcse_physics_notes/igcse_physics_notes_conduction_convection_and_radiation.html

4.What are relays and capacitors used for(other than storing energy)

Capacitors : are only used to store energy as Ex of it is ..... when u recharge ur mobile .. u insert a wire into the plug ....so ur Mobile is charging ..meaning it's storing Energy cuz it has a capacitor .......and once u detach it ...ur mobile is workin ..how come ? ..it's cuz there is a capacitor ...meaning in that case it works as an Exchange to the battery .

Relay : Well .. i got a lot to tell  uabt this ....but i guess it's too much for me to write down lol ..so i'll try my best to find u gd notes somewhere iA


5.Describe the action of a transistor as an electrically operated switch and show understanding of its use in switching circuits.

For this i never got a satisfying answer from any of my teachers ..so  i would say ... i only understood by answering a Q abt it i think in the June or Nov 2009 sessions .....

http://www.astarmathsandphysics.com/igcse_physics_notes/igcse_physics_notes_transistors.html

6.Recognize and show understanding of circuits operating as light sensitive switches and temperature operated alarms(using a relay or transistor)


the ones i didn't know how to answer u , ask Vin abt it ,I'm sure he'll have diagrams for a full explanation of them


7.Explain and use the terms analogue and digital.

the only thing i ever knew abt these two is the following :

What is the Difference between analogue and digital meters ? *

Analogue Meter shows reading by a deflecting pointer while Digital meter shows reading by Numbers and Digits.


as for the last one .....I don't have the Syllabus in my hand ..so What does it talk abt ?  

[The Golden Girl =D]

this site will really help u if u have more doubts

http://www.astarmathsandphysics.com/igcse_physics_notes_menu.html

[HUSH1994]

Thanks alot,don't worry i understood all,im the smartest guy in the class

[The Golden Girl =D]

Thanks alot,don't worry i understood all,im the smartest guy in the class

Anytime ...I'm glad u did

[The Golden Girl =D]

Thanks alot,don't worry i understood all,im the smartest guy in the class

What abt this one {and the whole 4.5 section except c.} ?

[HUSH1994]

it is ac\dc motors,generators,these are the hardest things i ever studied :S

[elemis]

it is ac\dc motors,generators,these are the hardest things i ever studied :S

HAHAHAHAHA !!!!

You dont know the meaning of hard. Wait till you get to A- Levels. Your gonna have a mental workout that will leave you brain dead.

Nah, just kidding..... or am I ?

To be honest, AC Generators and DC motors are hard to understand at first - you just got to find a good image to look at. 

[The Golden Girl =D]

it is ac\dc motors,generators,these are the hardest things i ever studied :S

I have explained a part of it to a member earlier , here u go :


D.C motor and an A.C generator. i do not understand the formula and have still not get an appropriate and concise explanation  of the magnetic fields concerning them and how the rotate continuously.

ans: 1. MOTOR changes electric energy to kinetic  while GENERATOR changes kinetic energy to electric.

2. D.c motor has got a circuit connected to it that has a battery in it while the generator has a circuit connected to it which has got anythin BUT a battery *ex : lamb or voltmeter ...etc*

3. The current in the motor is DC meaning a direct current cuz BATTERIES allow only direct current to pass ,while the generator has got somthin called slip rings which allows the wires to rotate freely in both clockwise and anticlockwise which produces an AC current .

4. You use the right hand rule for GENERATORS and the left hand rule for MOTORS

[The Golden Girl =D]

it is ac\dc motors,generators,these are the hardest things i ever studied :S

mafi shai isma AC/DC MOTOR !!! .......il MOTOR is DC wi bas ...lakin il generator fi minu AC o fi DC

I'll try my best ot explain just gimme some time

[elemis]

DC Motors - require a Split Ring

AC Generator - require a Slip Ring                               NOTE: You dont need to know about AC motors or DC generators.

DC Motors - Electrical Energy---> K.E.

AC Gen - K.E ----> Electrical Energy

------------------------------------------------------------------------------------------------------------------------------------

DC MOTOR - Why do you need a SPLIT RING ?

Every half turn the gaps in the Split ring are in line with the carbon brushes such that the current stops flowing. Due to its momentum the coil continues to turn until the carbon brushes have reversed contacts such that the current flows in the opposite direction.