Which of the following figure represents the variation of the particle momentum and the associated de Broglie wavelength?

An electron is moving through a field. It is moving $\left(\mathrm{i}\right)$ opposite to an electric field, $\left(\mathrm{ii}\right)$ perpendicular to a magnetic field as shown. For each situation, the de Broglie wavelength of the electron is:

The potential energy of a particle of mass, $m$ is given by:

$U\left(x\right)=\left\{\begin{array}{ll}{E}_0;& 0\le x\le 1\\ 0;& x>1\end{array}\right.$

${\lambda }_1$ and ${\lambda }_2$ are the de Broglie wavelengths of the particle, when $0\le x\le 1$ and $x>1$ respectively. If the total energy of particle is $2E_0$, the ratio $\frac{{\lambda }_1}{{\lambda }_2}$  will be:

A particle moves in a closed orbit around the origin, due to a force which is directed towards the origin. The de Broglie wavelength of the particle varies cyclically between two values ${\lambda }_1$ and ${\lambda }_2$ with ${\lambda }_1>{\lambda }_2$. Which of the following statements are true?