State the de Broglie principle.

The de-Broglie wavelength associated with a particle of mass $10^{-6} \ kg$ moving with a velocity of $10 \ ms^{-1}$ is:

If $\lambda _L, \lambda _M$ and $\lambda _N$ are the wavelengths of an electron in $L, M, N$ energy levels of $H^{-}$ atom respectively,what is their decreasing order?

The following plot represents the de-Broglie wavelength $(\lambda)$ as a function of $\frac{1}{\sqrt{K.E.}}$ for two particles $A$ and $B$. Identify the correct relation between their masses ($m_A$ and $m_B$).

Dual behavior of matter proposed by de Broglie led to the discovery of electron microscope, often used for the highly magnified images of biological molecules and other types of material. If the velocity of the electron in this microscope is $1.6 \times 10^{6} \,ms^{-1}$, calculate the de Broglie wavelength associated with this electron.

The de-Broglie wavelength $(\lambda)$ for electron $(e)$, proton $(p)$ and $He^{2+}$ ion $(\alpha)$ are in the following order. (Speed of $e$, $p$ and $\alpha$ are the same)