Question

why we cannot see the wavelength of a moving Car ?​

Answer 1

the mass of a moving car is very high so u are not able to see its wavelenght.

its related to heisenberg's uncertainity principle.

Answer 2

Because the de Broglie wave length of large objects is tiny.

λ=hp

where h is the Planck constant h=6.626∗10−34m2kgs−1

and p is the object’s momentum where p=mv

So we can say λ=hmv

Consider a basic object, say a 1kg mass going at 10ms−1.

Its de Broglie wavelength is:

λ=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∗10−31kg and say a velocity v=5000ms−1.

The de Broglie wavelength is λ=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.)