A 20 nC point charge is held stationary in an arbitrary elec

A 2.0 nC point charge is held stationary in an arbitrary electric field. The electric potential at the point that the charge is being held is 4.5V.

a. What is the charge\'s potential energy? Assume that the charge\'s potential energy is zero at points where the potential is zero (Give your answer in eV.)

b. The charge is moved to a point where the electric potential is 6.4V. How much work was done to move it? (Give your answer in Joules.)

c. How much work would be required to move a -3:0 C charge between the same two points? (Give your answer in eV.)

Solution

a) we have change in potential energy = PE_4.5 -PE ₀= q*V = 2x10^-9 * 4.5 = 9x 10 ^-9 J

now , 1 eV = 1.6 x10-19 J

so, 9x 10 ^-9 J= 1.442 x10^-27

b)we have work done = change in potential energy = PE_6.4 -PE _4.5=q*( 6.4-4.5)= 3.8 x10^-9 J

c) work done = change in potential energy = PE_6.4 -PE _4.5=q*( 6.4-4.5)=3x10^-9*( 6.4-4.5)= 5.7 x10^-9 J

now,5.7 x10^-9 J = 9.1324x10^-28