MCQ
If two vectors $2 \hat{i}+3 \hat{j}-\hat{k}$ and $-4 \hat{i}-6 \hat{j}-\lambda \hat{k}$ are parallel to each other then value of $\lambda$ be
- A2
- ✓3
- C4
✓
Answer
Correct option: B.
3
(b) Let $\vec{A}=2 \hat{i}+3 \hat{j}-\hat{k}$ and $\vec{B}=-4 \hat{i}-6 \hat{j}+\lambda \hat{k}$ $\vec{A}$ and $\vec{B}$ are parallel to each other$\frac{a_1}{b_1}=\frac{a_2}{b_2}=\frac{a_3}{b_3} \text { i.e. } \frac{2}{-4=\frac{3}{-6}=\frac{-1}{\lambda} \Rightarrow \lambda=2 .$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
When work is done on a body by an external force, its
$K_\alpha$ characteristic $X$-ray refers to the transition
→Two lenses have focal lengths $f_1$ and $f_2$ and their dispersive powers are $\omega_1$ and $\omega_2$ respectively. They will together form an achromatic combination if
→The image formed by an objective of a compound microscope is
A ray of light passes through an equilateral glass prism in such a manner that the angle of incidence is equal to the angle of emergence and each of these angles is equal to $3 / 4$ of the angle of the prism. The angle of deviation is
→In a hydrogen atom, which of the following electronic transitions would involve the maximum energy change
Two circular coils have their centres at the same point. The mutual inductance between them will be maximum when their axes
The only possibility of heat flow in a thermos flask is through its cork which is $75 \mathrm{~cm}$ in area and $5 \mathrm{~cm}$ thick. lts thermal conductivity is $0.0075 \mathrm{cal} / \mathrm{cmsec} \mathrm{C}$. The outside temperature is $40 \mathrm{C}$ and latent heat of ice is $80 \mathrm{cal} \mathrm{g}$. Time taken by $500 \mathrm{~g}$ of ice at $0 C$ in the flask to melt into water at $0 C$ is
→The refractive index of a prism for a monochromatic wave is $\sqrt{2}$ and its refracting angle is $60^{\circ}$. For minimum deviation, the angle of incidence will be
→A Gallilean telescope has objective and eye-piece of focal lengths $200\ \mathrm{cm}$ and $2 \mathrm{~cm}$ respectively. The magnifying power of the telescope for normal vision is
→