Mathematics MCQS for class 12 with Answers Chapter 7

Ifu=a₁i + b₁j +c₁k & v =a₂i +b₂j + c₂k be two non-zero vectors then u.v=

1

a₁b₁c₁ + a₂b₂c₂

a₁a₂ + b₁b₂ + c₁c₂

0

Two vectors are said to be equal, if they have _______ magnitude and ________ direction

Same, opposite

Same , same

Opposite, same

Opposite, opposite

Velocity, acceleration, force, weight are example of

Vectors

Both a and b

Unit vectors

Scalars

If cos ?,cos ? ,cos ? are direction cosines of a vector athen:

Cos?+Cos? +Cos?=0

Cos² ? + Cos² ? + Cos² ? = 1

Cos? Cos?

Cos? + Cos? + Cos? = 1

For two vectors j& k, we have: j.k=

0

1

-1

2

For two vectors a&b :a.b=

a + b

a – b

ab

The dot product of unit vector k with unit vector k is

2

None of these

1

0

Moment of a force about a point is:

Vector quantity

None of these

Scalar quantity

zero

The dot product of unit vector j with unit of vector i is

3

2

1

0

2i x 2j . k =

2

3

0

4