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5 Feb 2012 12:36:07 IST

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433

HCV QUESTION

Physics

a proton and an electron are accelerateed by same potential differnce . Let l nd p denote the de Brogli wavelength of the electron and the proton respectivly

a) l = p

b) l < p

c) l > p

d) the relation depends on accelerating pot. deifference.

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Comments (13)

sidharthsekharsahoo

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5 Feb 2012 13:45:22 IST

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i think I=p

Aakanksha Sangwan

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5 Feb 2012 15:35:36 IST

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even i thought so .......... but the ans is : l

Aakanksha Sangwan

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5 Feb 2012 15:36:24 IST

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the ans is -- l < p u may refer to hcv part2 , pg - 364

Aakanksha Sangwan

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5 Feb 2012 15:37:01 IST

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the ans -- l>p

shivansh shrivastava

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5 Feb 2012 17:07:06 IST

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As thy r acclratd at same p0tential,th energy 'qV' is equal,by th formula of de-brogli wavelngth,their mas wil decide th wavlngth,th one with greater mas wil hav smalr wavlngth,as lambda is inversly relatd to sq.ro0t of mas. . .i thnk mas of prot0n is greater,so it wil hav smal wavlngth

sidharthsekharsahoo

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5 Feb 2012 18:33:31 IST

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srivastava is the velocity same for both? if it is same then lamda inversly related to sq.root of mass .

sidharthsekharsahoo

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5 Feb 2012 18:55:03 IST

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yes w=qv is same for both . so the net gain in K.Eof both is also same.

w=qv=1/2m₁v₁² 1 for electron

w=qv=1/2m₂v₂²2 for proton

from above m₁/ m₂=(v₂/ v₂)^{2....................................}A

the de Brogli eqn for e is I=h / m₁v_{1.....................}1

the de Brogli eqn for proton p=h/m₂v_{2 ...................}2

from 1 and 2

I/p=m₂v₂/ m₁v₁................................B

from eqn A v₂/ v₁=(m₁ / m₂ )^{1/2....................................}C

putting C in B

I/p=(m₂ / m₁)^1/2

as m₂>m₁

I>p

shivansh shrivastava

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5 Feb 2012 19:03:29 IST

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Vel0city wil n0t b same,as energies(qV gives kinetic energy)are same,bt mass diffrs,so vel0city wil n0t b same. . .cn u telme whch formula are u usin?its n0t velocity but kinetic energy in that f0rmula,as i remembr. . .

shree

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5 Feb 2012 21:44:26 IST

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l &p inversely proportional to Me & Mp.Mep

shree

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5 Feb 2012 21:49:03 IST

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l&p are inversely proprtional to square roots of mass but the ans. is not affected

shree

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5 Feb 2012 21:50:53 IST

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ans will be c.

shree

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5 Feb 2012 21:52:48 IST

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velocities will not be same

MIHIR K CHHAYA

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6 Feb 2012 15:03:05 IST

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wave length = h / ( 2mE )^ 1/2 where E = qV is same

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