JEE Main 2019MathematicsThree Dimensional GeometryMediumMCQ

JEE Main 2019 — Three Dimensional Geometry Question with Solution

JEE Main 2019 (12 Jan Shift 1)

Question

A tetrahedron has vertices P1, 2, 1, Q2, 1, 3, R-1, 1, 2 and O0, 0, 0. The angle between the faces OPQ and PQR is

Choose an option

Show full solutionCorrect option: C
Correct answer
Ccos-11935

Step-by-step explanation

Vector perpendicular to face OPQ=i^j^k^121213=5i^-j^-3k^

Vector perpendicular to face PQR=i^j^k^21-11-12=i^-5j^-3k^

Angle between two faces cosθ=5+5+93535=1935

⇒θ=cos-11935

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About this question

This is a previous-year question from JEE Main 2019, covering the Three Dimensional Geometry chapter of Mathematics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.