Question 1

Paper 2Medium8 marks

An electron enters the region between two parallel plates as shown in Figure 1. The electric field between the plates is uniform. Ignore edge effects and the gravitational force on the electron. The electron has no initial vertical velocity.

+−e−vx = 2.0 × 107 m s−1400 V6.0 cm4.0 cm

The magnitude of the electron’s charge is 1.60×10−19 C1.60\times10^{-19}\ \mathrm{C} and its mass is 9.11×10−31 kg9.11\times10^{-31}\ \mathrm{kg}

(a)

State the direction of the electric force on the electron.

[1]
(b)

Calculate the magnitude of the electric field between the plates.

[1]
(c)

Calculate the magnitude of the electron’s acceleration between the plates.

[2]
(d)

Determine the vertical displacement of the electron from its entry point when it reaches the right end of the plates.

[3]
(e)

Determine the vertical component of the electron’s velocity at the instant it reaches the right end of the plates.

[1]

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