all eyez here!!!!!!!

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1)3 properties common 2 both beta & cathode rayz.
2)1 diff. between a nuclear bomb & nuclear reactor.
3) in a central heating system ,steam enters a radiator pipe at 100 degrees c. & water leaves the radiator pipe at 100 degree c.,can this radiator pipe heat a room?give xplanations 4 u'r answers.
gud luck solving it.none of this shit enters my head!!!!!!!!!

Subject: Re: all eyez here!!!!!!! Mon Feb 25, 2008 11:40 pm

1)i)Both produce fluorescence on stricking a fluorescent material
ii)are deflected by magnetic and electric fields
iii)Both are negetively charged with charge and mass equall to an electron.

2)An uncontrolled chain reaction occurs in a nuclear bomb.
A controlled chain reaction occurs in a nuclear reactor.

3)Yes, it can be used for heating aroom as latent heat is given out when steam cools to water.

Whats so difficult? confused

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easy 4 u 2 say.i've bunked most of my physics xams

Subject: Re: all eyez here!!!!!!! Tue Feb 26, 2008 9:44 pm

how come?

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i'm bad at physics!!!!!!!!

Subject: Re: all eyez here!!!!!!! Mon Jan 19, 2009 12:09 am

nuclear reactors (fission n fusion)
not in portion!!1

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Yes, Nuclear Fission and Fusion is Not there in the ICSE syllabus

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my teacher too told so n i didn't find it in the syllabus. i can leave it know??? confused

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yup u can leave it...no tension.. cheers

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thanx......john Happy

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hey plz ans dese......questions..i fell dey r impt but not getting d ans..plzzz help...........:----------

1.) 3cells of emf 'E' and internal resistnace 'r' are joined in parallel to a resistance 'R'. find the expression for the current across d resistance.....

2)can a radioactive substance emit both alpha nd beta particle simultaneously????????

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plz answer .if u no frnzzzzz

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1)Resistance 'R' is joined in parrallel so it will be at the same voltage as the battery..i.e.'E'.Since emf doesn't depend on int res, so 'r' is just to mislead you.
if the three cells are joined together in one line, then the total voltage is 3E,otherwise it will only be E

since V=IR
I=V/R
I=3E/R or E/R.

Hope itz right Very Happy

2) i hav read that a nucleus CANNOT

undergo simultaneous alpha n beta emmisions but i dunno why.
the alpha emission can be followed by another alpha emission till the nucleus becomes stable.it can also undergo a gamma emmision if the nucleus is in a excited state but never a beta.
same is the case fr beta emmisions.
hop dis ans is rite too kanika Very Happy

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sorry antony but even i dont no whether itzzz right or not dese questions ...................r from prctis papers from evergreen selfstudy.....dont no d answers vith surity...........

if anybody noosss d ans do rplyy!!!!... Very Happy

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second one is right...

first one the total voltage is E not 3E since it is parallel connection

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can u tell plzz y cant it go both types of emissions simultaneously itzz reallyy confusing???????????

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when the nucleus has high proton to neutron ratio, it is unstable.

unstable nucleus can emit only proton or neutron, to become stable, coz if it emits both, it will be unstable only. and i dont think Positive as well as negative particles can be emitted simultaneously.

when proton is emitted, it is alpha decay

when neutron is emitted, it is beta decay...

Guess, abhas can help....coz he is in 11 and might know more than us....?? bounce

thts all i know!!

will refer and tell..

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i guess you have given the right answer

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abhas...........we r waiting 4 u 4 the final answer

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i have the answer....i asked my phy sir...

radioactive decay reactions are all discrete reactions, i.e . they all happen only one after another..it happens in atoms having very high neutron to proton ratio....so, it is impossible for an atom to give out beta, alpha n gamma rays altogether....atom always gives out radiations one after another, either beta, alpha or gamma.....after alpha or beta decay, the atom is generally at an exciting state, i..e higher level of energy....to lower its state to the ground state, it gives out gamma radiations, after which it becomes stable.

for example, imagine picking up big marbles.....you can pick them only one at a time...you cant pick all of them at once....this radioactivity is a similar thing..

am i clear,...or nothing went into your cerebrum?

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that was good anu

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thank u so much anu........4 clearing my doubt.............

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kanika....its alryt...actually, even i had that question in my mind... Very Happy

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when n no. of cells are joined in parallel( assumin all have same emf E) net EMF = E.
assumn each has internal resistance r, effective internal resistance = n/r
EMF = I R EXTERNAL + I r internal,
here total r = R + n/r

I= E / R + n/r.

Whn cells joined in series

total EMF = n E
TOTAL INTERNAL R = nr

I = nE/ R + n r

But i believe cell connections ( series and parallel) NOT IN SYLLABUS

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is it? cell connection not in syll?