The cyclotron frequency of an electron gyrating in a magnetic field of $1\, T$ is approximately

The dispersive powers of the materials of two lenses forming an achromatic combination are in the ratio of $4: 3$. If the effective focal length of the two lenses is $+60 ~cm$,then the focal lengths of the lenses should be:

$A$ uniform cylinder of length $L$ and mass $M$ having cross-sectional area $A$ is suspended,with its length vertical,from a fixed point by a massless spring such that it is half-submerged in a liquid of density $\sigma$ at equilibrium position. The extension $x_0$ of the spring when it is in equilibrium is:

The shortest distance between the line $y-x=1$ and the curve $x=y^2$ is

$ABCDE$ is a pentagon. Forces $\overrightarrow{AB}, \overrightarrow{AE}, \overrightarrow{DC}, \overrightarrow{ED}$ act at a point. Which force should be added to this system to make the resultant $2\overrightarrow{AC}$?

An electrically charged particle enters a uniform magnetic field in a direction perpendicular to the field with a velocity $v$. Then,it travels