JEE Main 2023 · MathsMultiple choiceSingle correctMediumMulti-step

JEE Main 6 April 2023, Shift 1, Maths Q16

Question 16 of 90 in this shift, Maths question 16 of 30, Section A.

Let

\vec a=2\hat i+3\hat j+4\hat k

\vec b=\hat i-2\hat j-2\hat k

and

\vec c=-\hat i+4\hat j+3\hat k

. If

\vec d

is a vector perpendicular to both

\vec b

and

\vec c

, and

\vec a\cdot\vec d=18

, then

|\vec a\times\vec d|^2

is equal to

(1)640
(2)680
(3)720Official answer
(4)760

Official answer

Option 3

NTA final key.

Chapter: Vector Algebra
Topic: Cross Product
Idea tested: Lagrange's Identity

Same idea in other shifts

Asked 3× in all

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31 Jan 2024, Shift 1 · Q30Let $\vec{a}$ and $\vec{b}$ be two vectors such that $|\vec{a}|=1,\ |\vec{b}|=4$ , and $\vec{a}\cdot\vec{b}=2$ . If…MediumNumerical value

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 42 of the 174 JEE Main shifts held from 2017 to 2026.