If the kinetic energy of an electron is increased by $4$ times,what will be the change in its associated de Broglie wavelength?

Which one of the following explains light both as a stream of particles and as wave motion?

The de-Broglie wavelength associated with a material particle is

If $a_0$ is the Bohr radius,then the de-Broglie wavelength of an electron revolving in the second excited state of the $H$ atom will be:

The de Broglie wavelengths of two fast moving particles $X$ and $Y$ are $1 \ nm$ and $3 \ nm$ respectively. The mass of $X$ is nine times the mass of $Y$. The ratio of kinetic energies of $X$ and $Y$ is:

The mass of an electron is $9.1 \times 10^{-31} \ kg$. If its $K.E.$ is $3.0 \times 10^{-25} \ J$,calculate its wavelength.