An electron is projected with an initial speed 1.20×10 6 m/s into the uniform fi

Question

An electron is projected with an initial speed 1.20×106 m/s into the uniform field between the parallel plates in the figure(Figure 1) . Assume that the field between the plates is uniform and directed vertically downward, and that the field outside the plates is zero. The electron enters the field at a point midway between the plates.

Part A

If the electron just misses the upper plate as it emerges

from the field, find the speed of the electron

as it emerges from the field?

SubmitMy AnswersGive Up

An electron is projected with an initial speed 1.20×106 m/s into the uniform field between the parallel plates in the figure(Figure 1) . Assume that the field between the plates is uniform and directed vertically downward, and that the field outside the plates is zero. The electron enters the field at a point midway between the plates.

Part A

If the electron just misses the upper plate as it emerges

from the field, find the speed of the electron

as it emerges from the field?

SubmitMy AnswersGive Up

Explanation / Answer

Initial vertical velocity of the electron is zero.
Initial horizontal velocity of the electron is 1.2 x 10 m/s
Time taken to cross the plates = 0.02 / (1.2x10) = 16.7 ns

Given that the electron enters midway between the plates and it just misses the upper plate as it emerges. Hence the vertical displacement of the electron = 0.5cm = 0.005 m

The acceleration of the electron in the vertical direction is calculated as follows.
s = ut + 1/2 at²
0.005 = 0(16.7*10^9) + 1/2 a (16.7*10^9)²
a = 0.005 x 2 / (16.7*10^9)² = 3.59*10^13 m/s²

Now v = u + at = 0 +  3.59*10^13*16.7*10^-9 = 5.995*10^5 m/s

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.