first of all it is incorrect to say magnetic line of force.....we say only magnetic field lines.....bcoz the charged particle doesn't  always move in the direction of magnetic field  on experiencing the force unlike electrical field.....

 

secondly electrical field lines are not always pependicular to all surfaces.....

there are cases like electrical field  lines are perpendicular to equipotential surface...

 

well , in ur question u have not mentioned what kind of surface.....

so plz meention that...