The charge $q$ is fired towards another charged particle $Q$ which is fixed, with a speed $v$. It approaches $Q$ upto a closest distance $r$ and then returns. If $q$ were given a speed $2 v$, the closest distance of approach would be
A$r$
B$2 r$
C$\frac{r}{2}$
D$\frac{r}{4}$
Easy
Download our app for free and get started
D$\frac{r}{4}$
d (d)
$\frac{1}{2} m v^2=\frac{k q Q}{r}$
$\frac{1}{2} m(2 v)^2=\frac{k q Q}{r^{\prime}}$
$\frac{1}{4}=\frac{r^{\prime}}{r}$
$r^{\prime}=\frac{r}{4}$
Download our app
and get started for free
Experience the future of education. Simply download our apps or reach out to us for more information. Let's shape the future of learning together!No signup needed.*
Three concentric metallic spherical shell $A, B$ and $C$ or radii $a, b$ and $c$ $(a < b < c)$ have surface charge densities $- \sigma , + \sigma ,$ and $- \sigma $ respectively. The potential of shell $A$ is :
Two thin dielectric slabs of dielectric constants $K_1$ and $K_2$ $(K_1 < K_2)$ are inserted between plates of a parallel plate capacitor, as shown in the figure. The variation of electric field $E$ between the plates with distance $d$ as measured from plate $P$ is correctly shown by
A $500\,\mu F$ capacitor is charged at a steady rate of $100\, \mu C/sec$. The potential difference across the capacitor will be $10\, V$ after an interval of.....$sec$
If on the $x$-axis electric potential decreases uniformly from $60 \,V$ to $20 \,V$ between $x=-2 \,m$ to $x=+2 \,m$, then the magnitude of electric field at the origin
A capacitor of capacitance $1$ $\mu F$ withstands the maximum voltage $6$ $kV$ while a capacitor of $2$ $\mu F$ withstands the maximum voltage $4$ $kV$. What maximum voltage will the system of these two capacitor withstands if they are connected in series?......$kV$
Three capacitors of capacitance $3\,\mu \,F,\,10\,\mu \,F\,$ and $15\,\mu \,F\,$ are connected in series to a voltage source of $100\,V$. The charge on $15\,\mu \,F\,$is.......$\mu C$
A capacitor of $10 \mu \mathrm{F}$ capacitance whose plates are separated by $10 \mathrm{~mm}$ through air and each plate has area $4 \mathrm{~cm}^2$ is now filled equally with two dielectric media of $\mathrm{K}_1=2, \mathrm{~K}_2=3$ respectively as shown in figure. If new force between the plates is $8 \mathrm{~N}$. The supply voltage is . . . .. . .V.
Eight drops of mercury of equal radii possessing equal charges combine to form a big drop. Then the capacitance of bigger drop compared to each individual small drop is........$times$