Question
An electron of mass $m$ and charge $e$ is accelerated from rest through a potential difference $V$ in vacuum. The final speed of the electron will be
✓
Answer
(c) Kinetic energy $K = \frac{1}{2}m{v^2} = eV$ $==>$ $V = \sqrt {\frac{{2eV}}{m}} $
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
A ball of mass m moves with speed $v$ and it strikes normally with a wall and reflected back normally, if its time of contact with wall is $t$ then find force exerted by ball on wall
→An aeroplane in which the distance between the tips of wings is $50$ $m$ is flying horizontally with a speed of $360$ $km/hr$ over a place where the vertical components of earth magnetic field is $2.0 \times {10^{ - 4}}\,weber/{m^2}$. The potential difference between the tips of wings would be......$V$
→A particle of charge per unit mass $\alpha$ is released from origin with a velocity $\bar{v}=v_0 \vec{i}$ in a uniform magnetic field $\bar{B}=-B_0 \hat{k}$. If the particle passes through $(0, y, 0)$ then $y$ is equal to
→In the wave equation $y =0.5 \sin \frac{2 \pi}{\lambda}(400 t - x )\,m$ the velocity of the wave will be ......... $m / s$
→A cylindrical cavity of diameter a exists inside a cylinder of diameter $2$a shown in the figure. Both the cylinder and the cavity are infinitely long. A uniform current density $J$ flows along the length. If the magnitude of the magnetic field at the point $P$ is given by $\frac{N}{12} \mu_0$ aJ, then the value of $N$ is :
→Two identical conductors of copper and aluminium are placed in an identical electric fields. The magnitude of induced charge in the aluminium will be
A dimensionless quantity is constructed in terms of electronic charge $e$, permittivity of free space $\varepsilon_0$, Planck's constant $h$, and speed of light $c$. If the dimensionless quantity is written as $e^\alpha \varepsilon_0^\beta h^7 c^5$ and $n$ is a non-zero integer, then $(\alpha, \beta, \gamma, \delta)$ is given by
→The area of the plates of a parallel plate capacitor is $A$ and the gap between them is $d$. The gap is filled with a non-homogeneous dielectric whose dielectric constant varies with the distance $‘y’$ from one plate as : $K = \lambda \ sec(\pi y/2d)$, where $\lambda $ is a dimensionless constant. The capacitance of this capacitor is
→Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$
→Assertion $A:$ The binding energy per nucleon is practically independent of the atomic number for nuclei of mass number in the range $30$ to $170$.
Reason $R$ : Nuclear force is short ranged.
In the light of the above statements, choose the correct answer from the options given below on
An aircraft executes a horizontal loop with a speed of $150\, m/s$ with its wings banked at an angle of $12^o$. The radius of the loop is .......... $km$ $(g = 10\, m/s^2 \; and\; \tan 12^o = 0.2125)$
→