Question

. An electron falls through a small distance in a uniform electric field of magnitude 2 x 10-4 N/C. The direction of the field is reversed keeping the magnitude unchanged and a proton falls through the same distance. The time of fall will be [1]
(a) Same in both cases
(b) More in the case of an electron
(c) More in the case of proton
(d) Independent of charge

Answer 1

Answer:

correct answer is option c

Explanation:

please refer to the attached picture

t is proportional to √m

and proton have more mass than electron.

so, obviously, it will take more time

Answer 2

Answer:  (c) More in the case of proton

Explanation:

Given:

• Electric field = 2 x 10-4 N/C
• Direction of field is reversed.
• Magnitude remains the same.

To compare:

The time of fall of proton and electron.

Step-by-step explanation:

• Electric field (E) = F/q₀

       F is the force , q₀ is the charge.

      F = q₀ x E

       we know that F = ma (m is mass and a is acceleration)

     ma =  q₀ x E

        a = (q₀ x E) /m

• Distance(S) covered in Electric field is

       S = 1/2 at² ; t is the time required.

         substituting the value of a in the above equation we have,

      S = 1/2 at²

      S = 1/2 (q₀ x E) /m x t²

      t = $\sqrt{2Sm/q*E}$

      t² ∝ m

• Mass of proton = 1836 times of electron.
• Mass of proton > mass of electron.
• Time for proton > time for electron.

Thus the time taken in case of proton is more than the electron.

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