To calculate the de-Broglie wavelength of a particle, we use the formula: λ=‌
h
mv
where λ is the wavelength, h is Planck's constant, m is the mass of the particle, and v is the velocity of the particle. Given: Mass m=1mg=1×10−3g=1×10−6kg Velocity v=10m∕s Planck's constant h=6.63×10−34Js Substitute these values into the formula: λ=‌
6.63×10−34
1×10−6×10
=‌
6.63×10−34
10−5
=6.63×10−29m Therefore, the de-Broglie wavelength of the particle is 6.63×10−29m.