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A proton accelerated by potential difference 100 V have de-Broglie wavelength of lambda_(0) alpha-particle is accelerated by same potential different.Its de-Broglie wavelength will be ……

Answer»

`2sqrt(2)lambda_(0)`
`(lambda_(0))/(2sqrt(2))`
`(lambda_(0))/(SQRT(2))`
`(lambda_(0))/(2)`

Solution :`(1)/(2)mv^(2)`=eV
`THEREFORE m^(2)v^(2)=p^(2)=2meV`
Now `LAMBDA=(h)/(p)`
`therefore lambda=(h)/(sqrt(2meV))`
`therefore m^(2)v^(2)=p^(2)=2meV`
Now `lambda=(h)/(p)`
`therefore lambda=(h)/(sqrt(2meV))`
`therefore lambda prop (1)/(sqrt(me))`
`therefore (lambda_(alpha))/(lambda_(p))=sqrt((m_(p))/(m_(alpha)e_(alpha)))`
Now `m_(alpha)=4m_(p),e_(alpha)=2e_(p)`,
`therefore (lambda_(a))/(lambda_(p))=sqrt((m_(p)e_(p))/(4m_(p)xx2e_(p)))=(1)/(sqrt(8))`
`therefore (lambda_(alpha))/(lambda_(p))=(1)/(2sqrt(2))`
`therefore (lambda_(alpha))/(lambda_(0))=(1)/(2sqrt(2)) therefore lambda_(alpha)=(lambda_(0))/(2sqrt(2))`


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