68 practice questions on Vector Algebra , sorted Easy → Hard. Try each one first, then open its answer page for the worked explanation. Want the full theory first? Read the Vector Algebra notes .
x y a (4,1) b (2,3) a + b (6,4) Triangle law of vector addition: placing vector b at the head of vector a, the diagonal from the start to the final head gives the resultant a + b.
Easy - 20 questions Q5.
Two vectors are equal if they have the same:
A The same starting point in spaceB The same magnitude but possibly different directionC The same direction but possibly different magnitudeD Magnitude and directionShow answer & explanation →
Q10.
If a . b = 0 and neither a nor b is zero, then a and b are:
A ParallelB PerpendicularC EqualD Anti-parallelShow answer & explanation →
Q11.
The cross product i x i equals:
A 1 (a scalar value)B j (the unit vector)C k (the unit vector)D 0 (zero vector)Show answer & explanation →
Q13.
The position vector of point P(3, -2, 5) from the origin is:
A 3i + 2j - 5kB 3i - 2j + 5kC 3i + 2j + 5kD -3i + 2j + 5kShow answer & explanation →
Q15.
Collinear vectors are vectors that:
A Have exactly the same magnitude but any directionB Are perpendicular, meeting at a right angleC Have zero magnitude, making them null vectorsD Are parallel (lie along the same or parallel lines)Show answer & explanation →
Q18.
The triangle law of vector addition states that the third side of a triangle represents:
A a - bB a + bC a x bD a . bShow answer & explanation →
Q19.
A vector whose initial and terminal points are the same is called a:
A Position vectorB Unit vectorC Zero vectorD Free vectorShow answer & explanation →
Q20.
The parallelogram law of vector addition: |a + b|<sup>2</sup> + |a - b|<sup>2</sup> =
A 2|a|<sup>2</sup>B 2|b|<sup>2</sup>C 2(|a|<sup>2</sup> + |b|<sup>2</sup>)D 4(|a|<sup>2</sup> + |b|<sup>2</sup>)Show answer & explanation →
Medium - 20 questions Q22.
The angle between a = i + j and b = j + k satisfies:
A cos(theta) = 1/2B cos(theta) = 1C cos(theta) = 0D cos(theta) = sqrt(2)Show answer & explanation →
Q27.
If a = i + j + k, the unit vector in the direction of a is:
A i + j + kB (1/sqrt(2))(i+j+k)C (1/3)(i+j+k)D (1/sqrt(3))(i+j+k)Show answer & explanation →
Q28.
Three vectors a, b, c are coplanar if and only if:
A a x b x c = 0B a.(b x c) = 1C a.(b x c) = 0D a + b + c = 0Show answer & explanation →
Q29.
If a x b = 0 and both a and b are non-zero, then:
A a is perpendicular to bB a is parallel to bC a = bD a = -bShow answer & explanation →
Q30.
The section formula: point dividing AB in ratio m:n internally (position vectors a, b) has position vector:
A (ma + nb)/(m+n)B (na + mb)/(m+n)C (ma - nb)/(m-n)D (a + b)/2Show answer & explanation →
Q31.
The scalar triple product a.(b x c) gives:
A The area of triangle abc, half the cross product magnitudeB The perimeter of parallelepiped formed by edges a, b, cC The area of the base parallelogram spanned by b and cD The volume of the parallelepiped formed by a, b, cShow answer & explanation →
Q32.
The vector component of a perpendicular to b is:
A (a.b/|b|<sup>2</sup>)bB a + (a.b)bC a.(b/|b|)D a - (a.b/|b|<sup>2</sup>)bShow answer & explanation →
Q35.
If a + b + c = 0, then a.b + b.c + c.a =
A 0B (|a|<sup>2</sup>+|b|<sup>2</sup>+|c|<sup>2</sup>)/2C -(|a|<sup>2</sup>+|b|<sup>2</sup>+|c|<sup>2</sup>)/2D |a|<sup>2</sup>+|b|<sup>2</sup>+|c|<sup>2</sup>Show answer & explanation →
Q36.
The resultant of two equal vectors of magnitude F at angle theta has magnitude:
A 2FB F cos(theta)C F sin(theta)D 2F cos(theta/2)Show answer & explanation →
Q37.
The vectors |a| = 3, |b| = 2, a.b = 4. The angle theta satisfies:
A cos(theta) = 2/3B cos(theta) = 1C cos(theta) = 2D cos(theta) = 4/3Show answer & explanation →
Q40.
If a.b = a.c and a is non-zero, it necessarily means:
A b = c necessarily, in this particular caseB a is parallel to vector b specificallyC b - c = 0, meaning b and c are equalD a is perpendicular to (b - c)Show answer & explanation →
Hard - 28 questions Q41.
The vector triple product a x (b x c) equals (BAC-CAB rule):
A (a.c)b - (a.b)cB (a.b)c - (a.c)bC (b.c)a - (a.b)cD (a.c)b + (a.b)cShow answer & explanation →
Q43.
The scalar triple product satisfies:
A [a b c] = [a c b] (any swap is allowed)B [a b c] = -[b a c] but [a b c] = [b c a]C [a b c] = |a||b||c|, treating it as a simple magnitude productD [a b c] = (a x b).c = a.(b x c), a relation said to require coplanar vectors specificallyShow answer & explanation →
Q45.
The identity (a x b).(c x d) equals:
A (a.b)(c.d)B (a x c).(b x d)C (a.c)(b.d) - (a.d)(b.c)D (a.d)(b.c) - (a.c)(b.d)Show answer & explanation →
Q47.
The volume of the tetrahedron with one vertex at origin, others at a, b, c is:
A |[a b c]|B (1/3)|[a b c]|C (1/2)|[a b c]|D (1/6)|[a b c]|Show answer & explanation →
Q48.
The Lagrange identity states |a x b|<sup>2</sup> =
A (a.b)<sup>2</sup>B |a|<sup>2</sup>|b|<sup>2</sup> + (a.b)<sup>2</sup>C |a|<sup>2</sup>|b|<sup>2</sup> - (a.b)<sup>2</sup>D |a|<sup>2</sup> - |b|<sup>2</sup>Show answer & explanation →
Q50.
If a x b = a x c (a is non-zero), then necessarily:
A b = cB b - c is perpendicular to aC b - c is parallel to aD b + c = 0Show answer & explanation →
Q51.
For non-coplanar vectors a, b, c forming a basis, every vector r has a:
A A unique scalar multiple of vector a alone, ignoring b and cB A representation using the vector triple product r = a x b x cC Unique linear combination r = xa + yb + zcD A simple sum of all three basis vectors, r = a + b + cShow answer & explanation →
Q53.
If ABCD is a parallelogram with diagonal AC = p and BD = q, then AB =
A (p + q)/2B p + qC p - qD (p - q)/2Show answer & explanation →
Q54.
The equation of a line through point a and perpendicular to both b and c is:
A r = a + lambda*(b + c)B r = a + lambda*(b . c)C r = a + lambda*(b x c)D r = a + lambda*(b - c)Show answer & explanation →
Q55.
Using a.b = |a||b|cos(theta): angle between a = 3i+4j and b = 4i+3j satisfies:
A cos(theta) = 0B cos(theta) = 7/25C cos(theta) = 1D cos(theta) = 24/25Show answer & explanation →
Q59.
The vector equation of the plane through three points with position vectors a, b, c is:
A r . (b x c) = 0, a condition for a plane through the originB r = (a+b+c)/3, just the centroid pointC r = lambda*a + mu*b, missing the third point cD r = a + lambda*(b-a) + mu*(c-a)Show answer & explanation →
Q65.
A unit vector perpendicular to both i + j and j + k is:
A (i + j + k)/√3B (i − j + k)/√3C (i − j − k)/√3D (−i + j + k)/√3Show answer & explanation →