Physics Electric Charge and Field

Distilled water is one of the best examples of an electrical insulator. Very few ions are free and they are not enough to carry charge. But, if you look at tapwater or saltwater, it can be an effective conductor, as these liquids have dissolved salts and minerals acting as mobile charge carriers. They allow electricity to flow. 

The conductor needs to be in electrostatic equilibrium for the electrostatic field to become zero inside it. Any conductor will have electrons or electric charges that are moving freely inside the substance. When you apply an external electric field, these free electrons will redistribute until the time the internal field they create begins to cancel out the external field. That's why the total or net electric field inside the conductor becomes zero. 

You should know that electrons have a definite mass. The mass of a body increases a little when it gains electrons. The body mass can also slightly decrease if the body loses electrons during charging.

From Gauss law

$?=\frac{q_{enclosed}}{{\epsilon }_0}=\frac{5q}{{\epsilon }_0}$

For maximum value of s, initially, electron must move away from plate.

ut + $\frac{1}{2}$ at² = s

t = 1u = 1m/s               s = –1 m

1 * 1 – $\frac{1}{2}$ a * 1² = – 1

-> a = 4m/s²

$\frac{qE}{m}=4$      

  $\frac{q\sigma }{2{\epsilon }_{0}m}=4$     

$\sigma =\frac{4*2*9*10^{-12}*9*10^{-31}}{1.6*10^{-19}}$

$=\frac{8*81}{1.6}*10^{-24}$      

= 4.05 * 10^–22C/m²

Flux through a surface $\mathrm{?}=\stackrel{?}{E}.\stackrel{?}{A}$

$\mathrm{?}=\left(6\stackrel{?}{i}-4\stackrel{?}{j}+7\stackrel{?}{k}\right).200\stackrel{?}{i}$

$=1200unit$

Because E points along the tangent to the lines of force. If initial velocity is zero then due to the force, it always moves in the direction of E. Hence will always move on some lines of force

In Case I when both are positively charged, due to induction positive charge moves outwards on spheres, increasing effective distance between centres of charge causing magnitude of the force to decrease.

F₂₁ = QE₁ = λ₂l (2kλ₁/R)