Equipotential surfaces are to be drawn 100 V apart near a very large uniformly charged metal plate carrying a surface charge density σ = 0.75 μC/m2. How far apart (in space) are the equipotential surfaces?

Electric field due to uniformly charged metal plate is given by,

Here,

= Charge density

 Vacuum Permittivity

Our values are,

Replacing we have,

Now we have the relation where energy is equal to the change of the potential in a certain distance, then

Rearranging for the distance

Therefore the distance is 2.36mm

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.