You walk from your home to school, you walk back from your school to home. Outcome: you have walked two lots of the distance between your home and school but your resulting displacement is 0: you are now exactly where you started from. The sum of two vectors of the same magnitude but in opposite directions is 0.
Another example: try rowing a boat across a flowing stream. To go to the opposite bank you need to aim up-stream. Alternatively, if you try to row at right angles to the bank that you started from, you will end up downstream. These are examples of adding vectors that are acting at an angle to one another.
Electric field is a vector quantity, as it has both magnitude and direction. The direction of the electric field at a point is the direction of the force that a positive test charge would experience if placed at that point.
No, the curl of a vector field is a vector field itself and is not required to be perpendicular to every vector field f. The curl is related to the local rotation of the vector field, not its orthogonality to other vector fields.
Vector.
no
Scaler. The electric field is its vector counterpart.
Direction of the electric field vector is the direction of the force experienced by a charged particle in an external electric field.
If an electron enters a magnetic field parallel to the field lines (i.e., parallel to B), it will not experience any deflection or force due to the magnetic field. This is because the force on a charged particle moving parallel to a magnetic field is zero.
Yes, electric field intensity is a vector quantity because it has both magnitude and direction. The direction of the electric field intensity indicates the direction of the force that a positive test charge would experience if placed in that field.
in which field vector calculus is applied deeply
Charge is not a vector.
When one refers to the strength of a magnetic field, they're usually referring to the scalar magnitude of the magnetic field vector, so no.
Yes, every irrotational vector field is conservative because a vector field being irrotational implies that its curl is zero, which, by one of the fundamental theorems of vector calculus, implies that the vector field is conservative.