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Author Topic: ALL PHYSICS DOUBTS - POST HERE !!  (Read 230755 times)

Offline the_grim_reaper

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1410 on: May 25, 2010, 06:34:27 pm »
Quote from: ~VIN1094~ on May 25, 2010, 06:30:25 pm
oh sorry i didnt see urs ..potential difference required for producing cathode rays is really high to produce high energy electrons .. also d.c. is required .. think about it .. u want to produce electrons from the cathode .. if its ac than cathode and anode would constantly be changing ;)

hahahaah everyone from our class has a problem with AC and DC. Even I've asked that from VIN. Do you know why we've got a problem with AC and DC??? Cause we never really understood them. Our teacher says AC flows in two directions, DC in 1. (It's correct but not enough).End of story. Nothing else. So VIN, you may find it stupid, but I REALLY need you to please explain the what being AC or DC really means!!! :D
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Offline 8T

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1411 on: May 25, 2010, 06:35:13 pm »
Could some1 explain q 13 o/n 03 ?
I keep getting mixed up with manometers !!
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Offline Ivo

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1412 on: May 25, 2010, 06:36:43 pm »
Quote from: deadman786 on May 25, 2010, 06:34:27 pm
hahahaah everyone from our class has a problem with AC and DC. Even I've asked that from VIN. Do you know why we've got a problem with AC and DC??? Cause we never really understood them. Our teacher says AC flows in two directions, DC in 1. (It's correct but not enough).End of story. Nothing else. So VIN, you may find it stupid, but I REALLY need you to please explain the what being AC or DC really means!!! :D

I think this is it:

AC: alternating current (switches from positive to negative terminal and back to postivie)

DC: direct current (only flows from postivve to negative)

Also, please can someone answer my last post, thanks!
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Offline Ghost Of Highbury

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1413 on: May 25, 2010, 06:37:21 pm »
AC - The direction of current periodically reverses , positive to negative, negative to positive, positive to negative...and so on

DC  - is the unidirectional flow of electric charge
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Offline Ghost Of Highbury

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1414 on: May 25, 2010, 06:38:13 pm »
Quote from: Ivo on May 25, 2010, 06:29:52 pm
Please can you see if the following is accurate, please also confirm that heat loss is due to increase of current.


Yea heat loss is due to current. H = I^2r...(I^2)!!!

yes, its A, thicker.
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Offline Ivo

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1415 on: May 25, 2010, 06:38:24 pm »
Quote from: 8T on May 25, 2010, 06:35:13 pm
Could some1 explain q 13 o/n 03 ?
I keep getting mixed up with manometers !!

The answer is D, because pressure of gas is greater than pressure of air, so the side with gas pushes liquid, so get it? :D
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Offline diva_sparkles

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1416 on: May 25, 2010, 06:38:32 pm »
can sum1 plz tell me y is da anode cool in a CRO
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Offline Ivo

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1417 on: May 25, 2010, 06:39:33 pm »
Quote from: A@di on May 25, 2010, 06:38:13 pm
Yea heat loss is due to current. H = I^2r...(I^2)!!!

yes, its A, thicker.

What is H?  Never knew that formula.
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Offline Ivo

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1418 on: May 25, 2010, 06:40:36 pm »
Quote from: diva_sparkles on May 25, 2010, 06:38:32 pm
can sum1 plz tell me y is da anode cool in a CRO

This question came up in s06, so yes, please can someone explain.
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Offline Ghost Of Highbury

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1419 on: May 25, 2010, 06:40:45 pm »
Its just cooler than the hot cathode

H = Heat.
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Offline soraam

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1420 on: May 25, 2010, 06:40:51 pm »
Quote from: A@di on May 25, 2010, 06:38:13 pm
Yea heat loss is due to current. H = I^2r...(I^2)!!!

yes, its A, thicker.
is this rule in the syllabus ??????
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Offline Vin

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1421 on: May 25, 2010, 06:41:43 pm »
Quote from: Ivo on May 25, 2010, 06:31:11 pm
FYI, the p.d. you stated is 600V.

i didnt get u ?!? ??? :-[
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Offline diva_sparkles

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1422 on: May 25, 2010, 06:42:37 pm »
Quote from: A@di on May 25, 2010, 06:40:45 pm
Its just cooler than the hot cathode 

Thanks :)
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Offline Ghost Of Highbury

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1423 on: May 25, 2010, 06:42:44 pm »
Quote from: soraam on May 25, 2010, 06:40:51 pm
is this rule in the syllabus ??????

Guyz it is there in the syl..

Electrical Energy Transferred = I2R*t

assuming t = 1

Energy lost as heat energy = I^2r
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Offline soraam

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1424 on: May 25, 2010, 06:42:58 pm »
600 because 6 V is too low to make electrons with high energy to leave the coil
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