# Vector Algebra - Online Test

Q1. Vector has
Explaination / Solution:

A vector has both magnitude as well as direction.

Q2. Position vectors of points A, B, C, etc., with respect to the origin O are generally denoted by
Explaination / Solution:

Position vectors of any point in space are usually calculated from the origin, so we  write  three points A ,B,C  in space to represent the origin as the initial point.

Q3. Direction angles are
Explaination / Solution:

the angles are called direction angles, which the position vector makes with the positive x-axis ,y-axis and z-axis respectively

Q4. Direction cosines
Explaination / Solution:

Cosines of the angles α,β,γ are called direction cosines.

Q5. If l, m and n are direction cosines of the position vector OP the coordinates of P are
Explaination / Solution:

If l , m and n are the direction cosines of vector denoted by  , then , the coordinates of point P are given by : lr ,mr and nr respectively.

Q6. Zero Vector
Explaination / Solution:

A vector whose initial and terminal points coincides is called Zero Vector. The magnitude of Zero Vector is also Zero.

Q7. Unit Vector is
Explaination / Solution:

The vector whose magnitude is always 1 or unity is called a Unit Vector.

Q8. The unit vector in the direction of a given vectoris denoted by
Explaination / Solution:

, is called the unit vector of a given vector  in the direction of
Q9. Coinitial Vectors are
Explaination / Solution:

Two vectors whose initial point is same are called co- initial vectors.

Q10. Vectors A and B are Collinear
Explaination / Solution:

Two vectors A and B are said to be collinear , if they are parallel to the same line irrespective of their magnitudes and directions.