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Author Topic: ALL PHYSICS DOUBTS - POST HERE !!  (Read 229154 times)

Offline Raywin

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1170 on: May 25, 2010, 02:06:17 pm »
Quote from: misterioso on May 25, 2010, 01:58:33 pm
Can someone explain to me how the answer is B. I understand it has something to do with the capacitor, but why is it that voltmeter two is zero at all? Wouldnt none of them have become zero? Can anyone explain how the capaciter is working in this circuit???

I apologise for the crude picture

The ans is B. This is cause there is a complete circuit between volt meter 1 and the battery when the switch is opened. And the capacitor will be charging when the switch is closed. When the switch is opened again, it will discharge thus volt.meter 3 will show voltage. Thus these two volt. meters will show some voltage. So ans is B. Hope u got me.. :)
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Offline 8T

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1171 on: May 25, 2010, 02:08:44 pm »
Raywin ..I didnt.. More explanation please.
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Offline ambitious94

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1172 on: May 25, 2010, 02:09:57 pm »
I have a new question XD
What are nucleons? Neutrons or all the particles present in the nucleus?

Also
The north pole of a bar magnet is placed next to end P of an iron bar PQ, as shown. As a result,
magnetic poles are induced in the iron bar.
S (magnet) N     iron bar-->P Q

What are the magnetic poles induced at P and at Q?
magnetic pole at P magnetic pole at Q
A north north
B north south
C south north
D south south

Answer's C. I dont get it...I thght the N pole induced an N pole....:S
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Offline 8T

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1173 on: May 25, 2010, 02:11:30 pm »
Nucleons are protons + neutrons.
& Induction therefore attraction.. N IS ATTRACTED TO P.. And a magnet cannot have 2 north poles or south so the other one is south = C
« Last Edit: May 25, 2010, 02:14:21 pm by 8T »
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Offline rhea

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1174 on: May 25, 2010, 02:12:07 pm »
Quote from: ambitious94 on May 25, 2010, 02:09:57 pm
I have a new question XD
What are nucleons? Neutrons or all the particles present in the nucleus?

Also
The north pole of a bar magnet is placed next to end P of an iron bar PQ, as shown. As a result,
magnetic poles are induced in the iron bar.
S (magnet) N     iron bar-->P Q

What are the magnetic poles induced at P and at Q?
magnetic pole at P magnetic pole at Q
A north north
B north south
C south north
D south south

Answer's C. I dont get it...I thght the N pole induced an N pole....:S
actually i got a doubt related to this..
i always thought to induce magnetism, you have to stroke a magnet with the magnetic material.
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Offline jellybeans

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1175 on: May 25, 2010, 02:13:23 pm »
Quote from: ambitious94 on May 25, 2010, 02:09:57 pm
I have a new question XD
What are nucleons? Neutrons or all the particles present in the nucleus?

Also
The north pole of a bar magnet is placed next to end P of an iron bar PQ, as shown. As a result,
magnetic poles are induced in the iron bar.
S (magnet) N     iron bar-->P Q

What are the magnetic poles induced at P and at Q?
magnetic pole at P magnetic pole at Q
A north north
B north south
C south north
D south south

Answer's C. I dont get it...I thght the N pole induced an N pole....:S

nope!! when induction occurs , the N pole will induce a S pole on the iron barrrr cuz during induction, the magnet's repelling its same charge to the other side, leaving the surface nearest to N with the 'opposite charge'  so P will be south. :)
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holtadit

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1176 on: May 25, 2010, 02:14:32 pm »
Quote from: rhea on May 25, 2010, 02:12:07 pm
actually i got a doubt related to this..
i always thought to induce magnetism, you have to stroke a magnet with the magnetic material.

See if this helps.




OR read it here if the image's too small :

http://www.le.ac.uk/se/centres/sci/selfstudy/mam9.htm
« Last Edit: May 25, 2010, 02:16:05 pm by Ari Ben Canaan »
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Offline Raywin

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1177 on: May 25, 2010, 02:15:10 pm »
Quote from: 8T on May 25, 2010, 02:08:44 pm
Raywin ..I didnt.. More explanation please.

Hmm.. see there is a complete circuit between the battery and voltmeter 1 meaning that current will flow from the battery through the voltmeter and then to the battery again. This happens even WHEN THE SWITCH IS OPEN. So, voltmeter 1 will NOT show zero. Now, the capacitor will charge up when the circuit was initially closed and when the switched is opened it will discharge, meaning that current will flow from the capacitor through the voltmeter3 and then to the capacitor again. This makes the voltmeter show a reading. Therefore it WILL NOT SHOW ZERO. Thus voltmeter 2 is the only one tht does show zero. :) Now?
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Offline Burhan.arshad

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1178 on: May 25, 2010, 02:15:58 pm »
Quote from: rhea on May 25, 2010, 02:12:07 pm
actually i got a doubt related to this..
i always thought to induce magnetism, you have to stroke a magnet with the magnetic material.
north pole induce north pole when you hit ot touch it with megnt......but when u just place it near it will induce opposite pole
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Offline Vin

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1179 on: May 25, 2010, 02:16:37 pm »
Quote from: misterioso on May 25, 2010, 01:58:33 pm
Can someone explain to me how the answer is B. I understand it has something to do with the capacitor, but why is it that voltmeter two is zero at all? Wouldnt none of them have become zero? Can anyone explain how the capaciter is working in this circuit???

I apologise for the crude picture

pics cool ;) i use w7 too ;)
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Offline Malak

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1180 on: May 25, 2010, 02:17:26 pm »
Quote from: ambitious94 on May 25, 2010, 02:09:57 pm
I have a new question XD
What are nucleons? Neutrons or all the particles present in the nucleus?

Also
The north pole of a bar magnet is placed next to end P of an iron bar PQ, as shown. As a result,
magnetic poles are induced in the iron bar.
S (magnet) N     iron bar-->P Q

What are the magnetic poles induced at P and at Q?
magnetic pole at P magnetic pole at Q
A north north
B north south
C south north
D south south

Answer's C. I dont get it...I thght the N pole induced an N pole....:S

No The pole is always opposite to that nearest of the permanent manget...In this case P is near to N of permanent magnet so it S
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Offline misterioso

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1181 on: May 25, 2010, 02:21:43 pm »
Quote from: Raywin on May 25, 2010, 02:06:17 pm
The ans is B. This is cause there is a complete circuit between volt meter 1 and the battery when the switch is opened. And the capacitor will be charging when the switch is closed. When the switch is opened again, it will discharge thus volt.meter 3 will show voltage. Thus these two volt. meters will show some voltage. So ans is B. Hope u got me.. :)

Wow thanks that explains a lot! I thought that the capacitor was the charge for the whole cicuit thats where i was getting confused!!! Now I know that the battery and capacitor were individual circuits

Quote from: ~VIN1094~ on May 25, 2010, 02:16:37 pm
pics cool ;) i use w7 too ;)

Yeah it is isnt it? Its got the sweetness of Vista but the speed of XP. Thanks for all the help, u even made the effort to edit the picture!!!
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Offline Malak

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1182 on: May 25, 2010, 02:23:44 pm »
Can anyone exaplain me the relation between volume and pressure...Why when the volume decreases the pressure increases?

Specifically in this question:
Wouldnt the volume remain same  ???
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Offline MasterMath

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1183 on: May 25, 2010, 02:25:53 pm »
What should i revise for paper 1 ? ive solved like from 2009-->2003 .. my average marks are 38-40 .. do i need to do till 1996 or revise anything?

Thanks
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Offline Vin

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1184 on: May 25, 2010, 02:28:04 pm »
Quote from: ang3l on May 25, 2010, 02:23:44 pm
Can anyone exaplain me the relation between volume and pressure...Why when the volume decreases the pressure increases?

Specifically in this question:
Wouldnt the volume remain same  ???

answer is C ..

Volume is inversely proportional to Pressure .. as pressure increases volume decreases .. or vise versa  

k= constant

p = k/V

pV = k

explaining the molecules .. when pressure is applied the molecules come closer hence are 'compressed' so they are reduced in volume 
« Last Edit: May 25, 2010, 02:31:02 pm by ~VIN1094~ »
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