The electron moves from a point, the potential of which is 400V, with zero initial velocity.

The electron moves from a point, the potential of which is 400V, with zero initial velocity. What speed will it acquire at a point with a potential of 525V?

φ1 = 400 V.

φ2 = 525 V.

q = 1.6 * 10 ^ -19 Cl.

m = 9.1 * 10 ^ -31 kg.

V0 = 0 m / s.

V -?

Let us use the law of conservation of energy: the potential energy of the electron Wp is converted into the kinetic energy of the motion of the electron Wk: ΔWp = ΔWk.

ΔWп = q * (φ2 – φ1).

ΔWk = m * (V ^ 2 – V0 ^ 2) / 2.

Since V0 = 0 m / s, the formula will take the form: ΔWk = m * V ^ 2/2.

q * (φ2 – φ1) = m * V ^ 2/2.

V = √ (2 * q * (φ2 – φ1) / m).

V = √ (2 * 1.6 * 10 ^ -19 C * (525 V – 400 V) / 9.1 * 10 ^ -31 kg) = 6.6 * 10 ^ 6 m / s.

Answer: the speed of the electron will become V = 6.6 * 10 ^ 6 m / s.