Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
MHT CET202523 Apr 2025Morning ShiftPhysicsMathematics in PhysicsActual

If P =b i +6 j + k and Q = i -a j +4 k are perpendicular to each other, also 3 b-a=5 . The value of a and b is

Options

  1. Aa=2, b=1
  2. Ba=1, b=2
  3. Ca=2, b=3
  4. Da=4, b=3

Correct answer

B. a=1, b=2

Step-by-step solution

The vectors P = b i + 6 j + k and Q = i - a j + 4 k are perpendicular. Their dot product equals zero: P Q = b 1 + 6 (-a) + 1 4 b - 6a + 4 = 0 Given the relation 3b - a = 5 , express b in terms of a from the first equation: b = 6a - 4 Substitute into the second equation: 3(6a - 4) - a = 5 18a - 12 - a = 5 17a = 17 a = 1 b = 6(1) - 4 = 2 Comparing with the options, the pair a=1 , b=2 corresponds to option B .

Practice Mathematics in Physics on Quantrex Academy →

More from Mathematics in Physics

Which of the following statements is/are true? (A) Three vectors not lying in a plane give zero resultant (B) Three vectors lying in a plane can give zero resultant (C) Two vectors 2026Forces A and B act at a point. The sum of their magnitudes is 50 N and the magnitude of their resultant is 20 N. If the resultant is at 90^ with the smaller force, the magnitudes o 2026If two vectors A = 4 i + n j + 2 k and B = 2 i + 2 j - k are mutually perpendicular to each other then value of 'n' is 2026A physical quantity x is related as x = a b^2 c^3 d⁻⁴ . Relative errors in the quantities a , b , c and d are 2%, 1%, 3% and 4% respectively. Relative error in x will be 2026The percentage error in the measurement of mass of a body and its speed are 0.73 % and 1.84 % respectively. The percentage error in the measurement of its momentum and kinetic ener 2026The area of parallelogram formed by vectors P = 2 i - j + 5 k and Q = 3 i - 2 j + 4 k is 2026A cuboid has volume V = l l l , where l is the length of one side. When the length l is measured by a meter scale of least count 1 , mm , the relative percentage error in the measu 2026For two vectors P and Q , P Q = | P Q | The magnitude of R = P + Q is ( 45^ = 1 2 ) ? 2026 Full Mathematics in Physics list All MHT CET PYQs