MereTeacher

JEE • NEET • FOUNDATION

JEE · NEET Previous Year Question

$If A = 2 i + 3 j + 8 k is perpendicular to B = 4 j - 4 i + α k, then the value of ' α' is$

Topic: JEE PYQ

Answer: D. Full step-by-step solution below.

A $1$
B $\frac{1}{2}$
C $-1$
D $- \frac{1}{2}$

Correct answer: D

Solution

(d): A is perpendicular to B . ∴ A \cdot B = 0 or (2 i + 3 j + 8 k) \cdot (- 4 i + 4 j + α k) = 0 - 8 + 12 + 8 α = 0 or α = - 1/2

More Kinematics PYQs

$A river has a steady speed of ' v'. A man swims upstream at a distance of 'd' and swims back to the starting point in total ti\dots$
$Velocity (v) and acceleration (a) in two systems of n units 1 and 2 are related as v_{2} = \frac{n}{m ^{2}} v_{1}, and\dots$
$Two guns A and B can fire bullets at speeds 1 km / s and 2 km / s respectively. From a point on a horizontal g\dots$
$A car moving with a velocity of 20 m s^{- 1} is stopped in a distance of 40 m . If the same car is travell\dots$
$The speed of a particle changes from 5 ms^{- 1} to 25 ms^{- 1} in a time t . If the magnitude\dots$