If the deBroglie wavelength of an electron is equal to $10^{-3}$ times the wavelength of a photon of frequency $6 \times 10 ^ { 14 } \mathrm {~Hz}$, then the speed of electron is equal to: (Speed of light $= 3 \times 10 ^ { 8 } \mathrm {~m} / \mathrm { s }$, Planck's constant $= 6.63 \times 10 ^ { - 34 } \mathrm { J.s }$, Mass of electron $= 9.1 \times 10 ^ { - 31 } \mathrm {~kg}$)\\
(1) $1.1 \times 10 ^ { 6 } \mathrm {~m} / \mathrm { s }$\\
(2) $1.7 \times 10 ^ { 6 } \mathrm {~m} / \mathrm { s }$\\
(3) $1.8 \times 10 ^ { 6 } \mathrm {~m} / \mathrm { s }$\\
(4) $1.45 \times 10 ^ { 6 } \mathrm {~m} / \mathrm { s }$