Assertion : Let a =2 i +3 j - k , b =4 i +6 j -2 k , then a b = o Reason : If a o , b o…

Mathematics · JEE Advanced · NTA ExamsThree Dimensional Geometry

Assertion : Let \(\vec{a}=2 \hat{i}+3 \hat{j}-\hat{k}, \vec{b}=4 \hat{i}+6 \hat{j}-2 \hat{k},\) then \(\vec{a} \times \vec{b}=\vec{o}\)
Reason : If \(\overrightarrow{\mathrm{a}} \neq \overrightarrow{\mathrm{o}}\), \(\overrightarrow{\mathrm{b}} \neq \overrightarrow{\mathrm{o}}\) and \(\stackrel{\rightharpoonup}{\mathrm{a}}\) and \(\overrightarrow{\mathrm{b}}\) are non–collinear vectors, then \(\overrightarrow{\mathrm{a}} \times \overrightarrow{\mathrm{b}}\)= ab sin θ \(\hat{\mathrm{n}}\), where θ is the smaller angle between the vectors \(\stackrel{\rightharpoonup}{\mathrm{a}}\)and \(\overrightarrow{\mathrm{b}}\) and \(\hat{\mathrm{n}}\) is unit vector such that \(\overrightarrow{\mathrm{a}}, \overrightarrow{\mathrm{~b}}, \hat{\mathrm{n}}\)taken in this order form right handed orientation
  1. If both assertion and reason are correct and reason is the correct explanation of assertion.
  2. If both assertion and reason are true but and reason is not the correct explanation of assertion.
  3. If assertion is true but reason is false.
  4. If assertion is false but reason is true.
  5. If assertion and reason are both false.

Answer

(B) If both assertion and reason are true but and reason is not the correct explanation of assertion.

Sign up free on Edukali to view the step-by-step worked solution and practice thousands of similar questions.

Related practice questions

More Three Dimensional Geometry questions · Browse all practice questions