A particle of mass $m$ and charge $(-q)$ enters the region between the two charged plates initially moving along $x$ -axis with speed $v_{x}=2.0 \times 10^{6} \;m\, s ^{-1} .$ If $E$ between the plates separated by $0.5 \;cm$ is $9.1 \times 10^{2} \;N / C ,$ where will the electron strike the upper plate in $cm$?

$\left(|e|=1.6 \times 10^{-19} \;C , m_{e}=9.1 \times 10^{-31}\; kg .\right)$

Vedclass pdf generator app on play store
Vedclass iOS app on app store

Velocity of the particle, $v_{x}=2.0 \times 10^{6} \,m / s$

Separation of the two plates, $d =0.5\, cm =0.005\, m$

Electric field between the two plates, $E =9.1 \times 10^{2} \,N / C$

Charge on an electron, $q=1.6 \times 10^{-19} \,C$

Mass of an electron, $m _{ e }=9.1 \times 10^{-31} \,kg$

Let the electron strike the upper plate at the end of plate $L$, when deflection is s. Therefore,

$s=\frac{q E L^{2}}{2 m V_{x}^{2}}$

$\Rightarrow L=\sqrt{\frac{2 s m V_{x}^{2}}{q E}}$$=\sqrt{\frac{2 \times 0.005 \times 9.1 \times 10^{-31}}{1.6 \times 10^{-19} \times 9.1 \times 10^{2}}}$

$=\sqrt{0.00025}=0.016 \,m=1.6 \,cm$

Therefore, the electron will strike the upper plate after travelling $1.6 \;cm .$

Similar Questions

A particle of mass $1\ gm$ and charge $ - 0.1\,\mu C$ is projected from ground with a velocity $10\sqrt 2 $ at an $45^o$ with horizontal in the area having uniform electric field $1\ kV/cm$ in horizontal direction. Acceleration due to gravity is $10\ m/s^2$ in vertical downward direction. Select $INCORRECT$ statement

An inclined plane making an angle of $30^{\circ}$ with the horizontal is placed in a uniform horizontal electric field $200 \, \frac{ N }{ C }$ as shown in the figure. A body of mass $1\, kg$ and charge $5\, mC$ is allowed to slide down from rest at a height of $1\, m$. If the coefficient of friction is $0.2,$ find the time (in $s$ )taken by the body to reach the bottom. $\left[ g =9.8 \,m / s ^{2}, \sin 30^{\circ}=\frac{1}{2}\right.$; $\left.\cos 30^{\circ}=\frac{\sqrt{3}}{2}\right]$

  • [JEE MAIN 2021]

A particle of mass $m$ and charge $(-q)$ enters the region between the two charged plates initially moving along $x$ -axis with speed $v_{x}$ (like particle $1$ in Figure). The length of plate is $L$ and an uniform electric field $E$ is maintained between the plates. Show that the vertical deflection of the particle at the far edge of the plate is $q E L^{2} /\left(2 m v_{x}^{2}\right)$

Compare this motion with motion of a projectile in gravitational field

A uniform electric field of $10\,N / C$ is created between two parallel charged plates (as shown in figure). An electron enters the field symmetrically between the plates with a kinetic energy $0.5\,eV$. The length of each plate is $10\,cm$. The angle $(\theta)$ of deviation of the path of electron as it comes out of the field is  $.........$(in degree).

  • [JEE MAIN 2023]

An electron is projected in the direction of electric field. Just after projection of electron