1)It is said that separation between the two charges forming the dipole should be small, but small compared to what?
2)The electric potential decreases uniformly from 120 V to 80V as one moves on the X axis from -1 cm to +1cm. Why can the field at the origin be less than 20V/cm ?
3)Potential at a point should depend or not on the choice of zero potential or zero potential energy? If yes they why and if no then also why?
621) small compared to the system in which these two charges appear....
2) Field will be 20v/cm. (I dont know why this should happen!)
3) Potential at a point should depend on the choice of zero potential. Potential is the work done in moving a unit charge from one point to other..
It has nothing to do with potential energy. (Energy is the work done and will depend on electric field..)
1062) field in x direction will be 20v/cm but there may be components of electric field in other directions the info about which we have not been given, So it can be more/less than 20v/cm
11I am posting the full question (2nd one ) as it is given in HCV
2) The electric potential decreases uniformly from 120 V to 80V as one moves the X axis frm
x = -1cm to x = +1 cm. The electric field at the origin
a)must be equal to 20V/cm
b)may be equal to 20V/cm
c)may be grater than 20V/cm
d)may be less than 20V/cm
In book only option (b) and (c) are given as correct, but I think even option (d) should also be right.