An infinite nonconducting sheet has a surface charge density

An infinite non-conducting sheet has a surface charge density of 0.10 x 10^4 C/m^2. How far apart are the terminals (equipotential surfaces) if the potential difference 50 V? A two parallel plates separated by a distance of 2.00 mm and has potentials: V_1 = -70.0 V and V_2 = - 50.0 V. A proton moves from plate-1 (V_1) to plate-2 (V_2) with initial speed of 90.0 km/s. What is the electric potential energy experienced by the proton? What is the initial kinetic energy of the proton? Using conservation of energy, determine the change in kinetic energy of the proton.

Solution

Note: post your questions seperately.

7.

The electric field is,

   E = sigma/2e₀ = 0.10x10^-6 / 2*8.85x10^-12 = 5649.7175N/C

The distance is,

   d - -dV/E = - 50 / 5649.7175 = 8.8e-3 = 8.80 mm

therefore, option B is correct.