MCQ
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
- A$V\sqrt {e/m} $
- B$\sqrt {eV/m} $
- ✓$\sqrt {2eV/m} $
- D$2eV/m$
✓
Answer
Correct option: C.
$\sqrt {2eV/m} $
c
(c) Kinetic energy $K = \frac{1}{2}m{v^2} = eV$ $==>$ $V = \sqrt {\frac{{2eV}}{m}} $
(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 fish looking up through the water sees the outside world contained in a circular horizon. If the refractive index of water is $\frac{4}{3}$ and the fish is $12 \ cm$ below the surface, the radius of this circle in cm is
→From the figure describing photoelectric effect we may infer correctly that
Three straight parallel current carrying conductors are shown in the figure. The force experienced by the middle conductor of length $25\,cm$ is
→A nucleus of mass $M + \Delta m$ is at rest and decays into two daughter nuclei of mass $ \frac {M}{4}$&$\frac{3M}{4}$ each. Speed of light is $c.$ The speed of daughter nucleus of mass $\frac{M}{4}$ is
→In a $p-n$ junction diode, change in temperature due to heating
→A capacitor is connected to a cell of emf E having some internal resistance r. The potential difference across the
Two long coaxial and conducting cylinders of radius $a$ and $b$ are separated by a material of conductivity $\sigma$ and a constant potential difference $V$ is maintained between them, by a battery. Then the current, per unit length of the cylinder flowing from one cylinder to the other is -
→$\sigma_1$ and $\sigma_1$ are the electrical conductivities of Ge and Na respectively. If these substances are heated, then(a)(b) (c) (d)
→A radioactive reaction is $_{92}{U^{238}}{ \to _{82}}P{b^{206}}$. How many $\alpha $ and $\beta $ particles are emitted
→Some equipotential surfaces of the magnetic scalar potential are shown in the figure. Magnetic field at a point in the region is
