A proton and an $\alpha -$ particle (with their masses in the ratio of $1 : 4$ and charges in the ratio of $1:2$ are accelerated from rest through a potential difference $V$. If a uniform magnetic field $(B)$ is set up perpendicular to their velocities, the ratio of the radii $r_p : r_{\alpha }$ of the circular paths described by them will be
$1: \sqrt 2$
$1 : 2$
$1 : 3$
$1: \sqrt 3$
This question has Statement $1$ and Statement $2$ . Of the four choices given after the Statements, choose the one that best describes the two Statements.
Statement $1$: A charged particle is moving at right angle to a static magnetic field . During the motion the kinetic energy of the charge remains unchanged.
Statement $2$: Static magnetic field exert force on a moving charge in the direction perpendicular to the magnetic field.
An electron with energy $0.1\,ke\,V$ moves at right angle to the earth's magnetic field of $1 \times 10^{-4}\,Wbm ^{-2}$. The frequency of revolution of the electron will be. (Take mass of electron $=9.0 \times 10^{-31}\,kg$ )
The net charge in a current carrying wire is zero still magnetic field exerts a force on it, because a magnetic field exerts force on
An electron is projected along the axis of a circular conductor carrying some current. Electron will experience force
A particle of mass $M$ and charge $Q$ moving with velocity $\mathop v\limits^ \to $ describes a circular path of radius $R$ when subjected to a uniform transverse magnetic field of induction $B$. The work done by the field when the particle completes one full circle is