The de broglie wavelength of an electron is 8.7 ã 10-11 m. the mass of an electron is 9.1 ã 10-31 kg. the velocity of this electron is m/s.

wavelength of an electron l = h/p = 8.7 x 10^-11 h --> Planck's Constant m --> Momentum Wavelength l = h/p = h/mv = > v = h/(m*l) From the given values, m = 9.1 x 10^-31 kg l = 8.7 x 10^-11 m h = 6.626x10^-34 Js v = 6.626x10^-34/ ((9.1 x 10^-31)*(8.7 x 10^-11)) The velocity of electron v = 8.37x10^6 m/s