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CUET · MATHS · PYQ PAPER 2025

If \(\vec{a}=2 \hat{i}-\hat{j}+3 \hat{k}\) and \(\vec{b}=2 \hat{i}+2 \hat{j}+\hat{k}\) then
Match List-I with List-II
List-IList-II
(A) Projection of \(\vec{a}\) on \(\vec{b}\) is(I) \(-7 \hat{i}+4 \hat{j}+6 \hat{k}\)
(B) \(\vec{a} \times \vec{b}\) is(II) \(\frac{1}{\sqrt{101}}(-7 \hat{i}+4 \hat{j}+6 \hat{k})\)
(C) Unit vector along \(\vec{a}+\vec{b}\) is(III) \(\frac{5}{3}\)
(D) Unit vector perpendicular to both \(\vec{a}\) and \(\vec{b}\) is(IV) \(\frac{1}{\sqrt{33}}(4 \hat{i}+\hat{j}+4 \hat{k})\)

Choose the correct answer from the options given below :

  1. A (А) – (III), (В) – (IV), (C) - (I), (D) – (II)
  2. B (А) - (III), (В) – (I), (C) – (II), (D) – (IV)
  3. C (А) – (III), (В) - (I), (C) - (IV), (D) – (II)
  4. D (A) - (I), (B) – (IV), (C) – (II), (D) – (III)
Verified Solution

Answer & Solution

Correct Answer

(C) (А) – (III), (В) - (I), (C) - (IV), (D) – (II)

Step-by-step Solution

Detailed explanation

(A) Projection of \(\vec{a}\) on \(\vec{b}\): \(\vec{a} \cdot \vec{b} = (2)(2) + (-1)(2) + (3)(1) = 4 - 2 + 3 = 5\) \(|\vec{b}| = \sqrt{2^2 + 2^2 + 1^2} = \sqrt{4 + 4 + 1} = \sqrt{9} = 3\) Projection \( = \frac{\vec{a} \cdot \vec{b}}{|\vec{b}|} = \frac{5}{3}\) (Matches List-II…