If the position of an object is zero at a particular moment, this does not provide any indication about its velocity. It might simply be moving through that point, and you observed it exactly when it was at zero.
20.7 volts. The mass of an electron is 9.1 x 10⁻³¹ kg, and its wavelength is 0.27 x 10⁻⁹ m. The velocity of the electron can be determined using de Broglie's equation λ mv = h. Substituting the known values, we arrive at v = 2.7 x 10⁶ m/s. The potential difference through which the electron accelerates is noted, with the charge on an electron being 1.6 x 10⁻¹⁹ C. According to the conservation of energy, (0.5) mv² = q ΔV leads to ΔV = 20.7 volts.
