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Saturday, 31 October

JEE Main 2023 · MathsMultiple choiceSingle correctMediumCalculation

JEE Main 10 April 2023, Shift 2, Maths Q16

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

Let a⃗=2i^+7j^−k^, b⃗=3i^+5k^\vec{a} = 2\hat{i} + 7\hat{j} - \hat{k},\ \vec{b} = 3\hat{i} + 5\hat{k} and c⃗=i^−j^+2k^\vec{c} = \hat{i} - \hat{j} + 2\hat{k}. Let d⃗\vec{d} be a vector which is perpendicular to both a⃗\vec{a} and b⃗\vec{b}, and c⃗⋅d⃗=12\vec{c} \cdot \vec{d} = 12. Then (−i^+j^−k^)⋅(c⃗×d⃗)(-\hat{i} + \hat{j} - \hat{k}) \cdot (\vec{c} \times \vec{d}) is equal to
  1. (1)2424
  2. (2)4242
  3. (3)4444Official answer
  4. (4)4848

Official answer

Option 3

NTA final key.

Same idea in other shifts

Asked 2× in all
  1. 25 Jul 2021, Shift 1 · Q82Let p⃗=2i^+3j^+k^\vec{p}=2\hat{i}+3\hat{j}+\hat{k} and q⃗=i^+2j^+k^\vec{q}=\hat{i}+2\hat{j}+\hat{k} be two vectors. If a vector…EasyNumerical 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 108 of the 174 JEE Main shifts held from 2017 to 2026.