Question

The total number of lines of induction leaving a closed surface normally is called
A.Total normal electric field
B.Total normal electric induction
C.Total normal electric potential
D.Total normal electric flux

Answer 1

The number of lines of induction passing normally through a unit area in an electric field is called normal electric induction. Normal electric induction and total normal electric induction are two different terms these both occur when a charge is placed inside a closed body.

Complete answer:
Electric field is a region around a source charge, If in that region any other small charge is placed then that charge will experience a Coulomb’s force of attraction and repulsion due to that electric field. Electric field is always perpendicular to the surface to charge the body. For positive charge electric field lines are in outwards normal direction while for negative charge they are inwards normal direction.
When a charge is enclosed in a surface then electric field lines will come out from that closed surface normally then the total number of lines of induction leaving a closed surface normally is called total normal electric induction.
Total normal electric induction = (Normal electric Induction) (Total Surface Area).
In study of total normal electric induction we always considered the whole surface area of the closed surface while for the study of normal electric induction we always considered unit area. When electric field lines are considered in the unit area of a closed surface then we call it normal electric induction of that closed surface.
Total number of electric field lines that cross the surface normally is called total electric flux of that closed surface. If no charge is enclosed in a surface then electric flux is zero. Electric flux charge should be enclosed in any closed surface.
All terms are slightly different from each other like electric field is a region in which another charge will experience a force of attraction or repulsion while electric flux is defined as a number of electric field lines that passes through any surface normally.

Correct Option is (B).

Note:
Electric field is always normal to surface and area vector of surface also acts outwards normal direction i.e. Electric field and area vectors are in the same direction so total normal electric induction can be calculated by multiplying normal electric induction with area of surface.