A deuteron and a proton moving with equal kinetic energy enter into to a uniform magnetic field at right angle to the field. If $r_{d}$ and $r_{p}$ are the radii of their circular paths respectively, then the ratio $\frac{r_{d}}{r_{p}}$ will be $\sqrt{ x }: 1$ where $x$ is ..........

A charged particle is released from rest in a region of steady and uniform electric and magnetic fields which are parallel to each other. The particle will move in a

A proton of energy $8\, eV$ is moving in a circular path in a uniform magnetic field. The energy of an alpha particle moving in the same magnetic field and along the same path will be.....$eV$

An electron is projected with velocity $\vec v$ in a uniform magnetic field $\vec B$ . The angle $\theta$  between $\vec v$ and $\vec B$  lines between $0^o$ and $\frac{\pi}{2}$ . It velocity $\vec v$ vector returns to its initial  value in time interval of 

A charged particle is released from rest in a region of uniform electric and magnetic fields which are parallel to each other. The particle will move on a

An electron is moving along positive $x$-axis.Auniform electric field exists towards negative $y$-axis. What should be the direction of magnetic field of suitable magnitude so that net force of electron is zero