InterviewSolution
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InterviewSolution
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An electron of mass `m` with an initial velocity `vec(v) = v_(0) hat`(i) `(v_(0) gt 0)` enters an electric field `vec(E ) = v_(0) hat (i) `(E_(0) = constant gt 0)` at `t = 0` . If `lambda_(0)` is its de - Broglie wavelength initially, then its de - Broglie wavelength at time `t` isA. `lambda_(0)`B. `(lambda_(0))/(( 1 + (e E_(0))/(mv_(0)) t)`C. `lambda_(0) t`D. `lambda_(0) (1 + ( e E_(0))/(mv_(0)) t)` |
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Answer» Correct Answer - B `vec(v) = v_(0) hat (i)` `vec ( E ) = - E_(0) hat (i)` `vec (a) = vec(F)/(m) = (q vec( E))/(m) = ((-e) (-E_(0)) hat (i))/(m)` ` rArr vec (a) = ( e E_(0))/(m) hat (i)` `v = u + at` `v = v_(0) + (e E_(0))/(m) t` `lambda = (h)/(mv) = (h)/(m [ v_(0) + (e E_(0) t)/(m)])` `= (h)/(mv_(0) [ 1 + ( eE_(0) t)/(mv_(0))]) = (lambda_(0))/(1 + (e E_(0) t)/(mv_(0))` |
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