The acceleration of an electron in an electric field of magnitude $50\, V/cm$, if $e/m$ value of the electron is $1.76 \times {10^{11}}\,C/kg$, is
$8.8 \times {10^{14}}\,m/sec^2$
$6.2 \times {10^{13}}\,m/sec^2$
$5.4 \times {10^{12}}\,m/sec^2$
Zero
An oil drop of $12$ excess electrons is held stationary under a constant electric field of $2.55 \times 10^{4}\; N\,C ^{-1}$ (Millikan's oil drop experiment). The density of the oil is $1.26 \;g \,cm ^{-3} .$ Estimate the radius of the drop. $\left(g=9.81\; m s ^{-2} ; e=1.60 \times 10^{-19}\; \,C \right)$
Infinite charges of magnitude $q$ each are lying at $x =1,\, 2,\, 4,\, 8...$ meter on $X$-axis. The value of intensity of electric field at point $x = 0$ due to these charges will be
The intensity of electric field required to balance a proton of mass $1.7 \times {10^{ - 27}} kg$ and charge $1.6 \times {10^{ - 19}} C$ is nearly
For given arrangement, where four charge fixed at ends of as quare as given, find value of additional charge $Q$ to be put on one of the vertices so that component of net electric field along the vertical symmetric axis is zero at every point on the vertical
Write equation of electric field by system of $\mathrm{'n'}$ charges.