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QNEET-2018-Ph-915: NEET 2018 Physics - Class 12 NEET-2018-Ph-915 Solution: An electron falls from rest through a vertical distance h in a…
An electron falls from rest through a vertical distance h in a uniform and vertically upward directed electric field E. The direction of electric field is now reversed keeping its magnitude the same. A proton is allowed to fall from rest in it through the same vertical distance h. The time of fall of the electron in comparison to the time of fall of the proton is smaller 5 times greater 10 times greater equal
Multiple Choice Options
- A smaller
- B 5 times greater
- C 10 times greater
- D equal
Step-by-Step Verified Solution
Force experienced by a charged particle in
an electric field, F = qE
As F = ma
_ ma = qE
_ a = q E m
As electron and proton both fall from same height at
rest. Then initial velocity = 0
From the formula, s = ut + 1 2 a t 2
_ h = 1 2 a t 2
_ h = 1 2 q E m t 2
_ t = 2 h m q E
_ t _ m as �q� is same for electron and
proton.
Since, electron has smaller mass so it will take
smaller time.