Define position vector.

Define the position vector of a point with respect to an origin. If vec(a) " and " vec(b) are the position vectors of the points P and Q respectively, find the vector vec(PQ) in terms of vec(a) " and " vec(b) .

Find the position vector of the centroid of a triangle when the position vectors of the vertices are given.

Define unit vector, null vector and position vector .

(A) : When the observation point lies along the length of the current element, magnetic field is zero. (R) : According to Biot-Savart's law field is defined only when position vector of a point relative to current element is non zero.

Define Coinitial vector and Collinear vector .

Define unit vector, null vector and posi-tion vector .

Distinguish between position vector and displacement vector.