alleryQuestion 7: If the angle between vectors A and B is $\theta$, then the value of the product $(B\times A).A$ is equal to
ABA² cos θ
BBA² sin θ
Czero
DBA² sin θ cos θ
Answer & Solution
Correct answer: C. zero
B×A will be perpendicular to both A and B.
$$
(B \times A).A = (B \times A)A \cos \theta \text{ (here } \theta = 90^\circ\text{)}
$$
$$
= |B \times A| |A| \cos 90
$$
$$
= 0
$$
Hence option c is the answer.
Keep practising General Knowledge
Browse all General Knowledge questions for JEE Advanced, or explore more General Science topics.
Related questions
Which statement best defines work done by a force in mechanics?Work done by a force on a body is negative when:In an ideal pendulum oscillating without air resistance, which quantity remains constant?Which of the following is an example of elastic potential energy?According to the work-energy theorem, the net work done on a particle is equal to:In a system where only conservative forces act, which quantity remains constant?Average power is defined as:Instantaneous power delivered by a force is best expressed as: