- A 1.87*10^6 m/s
- B 2.65*10^6 m/s
- C 7.02*10^12 m/s
- D 3.2*10^-19 m/s
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Answer:
B
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The potential difference between the plates is equal to the change in electric potential energy of the electron. The potential difference is given by V = Ed, where E is the electric field intensity between the plates and d is the distance between them. The electric field intensity E = V/d = 20V/0.1m = 200 V/m. The change in electric potential energy is qV, where q is the charge of the electron (-1.6*10^-19 C). Setting the change in potential energy equal to the change in kinetic energy (0.5mv^2), we have qV = 0.5mv^2. Solving for v, we get v = sqrt(2qV/m) = sqrt(2*(-1.6*10^-19 C)*(20V)/(9.11*10^-31 kg)) ≈ 2.65*10^6 m/s.
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