An electron revolves around an infinite cylindrical wire having uniform linear change density $2 \times 10^{-8}\,Cm ^{-1}$ in circular path under the influence of attractive electrostatic field as shown in the figure. The velocity of electron with which it is revolving is $.........\times 10^6\,ms ^{-1}$. Given mass of electron $=9 \times 10^{-31}\,kg$
$4$
$2$
$8$
$6$
A point charge $ + q$ is placed at the centre of a cube of side $L$. The electric flux emerging from the cube is
Draw electric field by negative charge.
A few electric field lines for a system of two charges $Q_1$ and $Q_2$ fixed at two different points on the $x$ -axis are shown in the figure. These lines suggest that:-
The magnitude of the average electric field normally present in the atmosphere just above the surface of the Earth is about $150\, N/C$, directed inward towards the center of the Earth . This gives the total net surface charge carried by the Earth to be......$kC$ [Given ${\varepsilon _0} = 8.85 \times {10^{ - 12}}\,{C^2}/N - {m^2},{R_E} = 6.37 \times {10^6}\,m$]
How does the electric field lines depend on area ?