Question

Why is the de broglie wavelength associated with macroscopic object not observed in daily life

Answer 1

Because the de Broglie wave length of large objects is tiny.
λ=hpλ=hp
where hh is the Planck constant h=6.626∗10−34m2kgs−1h=6.626∗10−34m2kgs−1
and pp is the object’s momentum where p=mvp=mv
So we can say λ=hmvλ=hmv
Consider a basic object, say a 1kg1kg mass going at 10ms−110ms−1.
Its de Broglie wavelength is:
λ=6.626∗10−34m2kgs−11kg ∗ 10ms−1=6.626∗10−35mλ=6.626∗10−34m2kgs−11kg ∗ 10ms−1=6.626∗10−35m
which is absolutely tiny.
So there are no discernible wave properties to be observed on the large scales.
(To compare, look at the de Broglie wavelength of an electron with mass m=9.11∗10−31kgm=9.11∗10−31kg and say a velocity v=5000ms−1v=5000ms−1.
The de Broglie wavelength is λ=1.45∗10−7m=145nmλ=1.45∗10−7m=145nm
This is on the nanometre scale which is the same range as the ‘standard’ parts of the electromagnetic spectrum, so the electron’s wave properties are important.)