मराठी

A Unit Vector Perpendicular to Both ^ I + ^ J and ^ J + ^ K is - Mathematics

Advertisements
Advertisements

प्रश्न

A unit vector perpendicular to both \[\hat{ i }  + \hat{ j } \text{ and }  \hat{ j } + \hat{ k } \] is

 

पर्याय

  • \[\hat{ i }  - \hat{ j }  + \hat{ k } \]

  • \[\hat{ i }  + \hat{ j }  + \hat{ k } \] 

  • \[ \frac1 {\sqrt3}  ( \hat{ i }  + \hat{ j }  + \hat{ k } ) \] 

  • \[ \frac1 {\sqrt3}  ( \hat{ i }  - \hat{ j }  + \hat{ k } ) \] 

MCQ
Advertisements

उत्तर

\[ \frac1 {\sqrt3}  ( \hat{ i }  - \hat{ j }  + \hat{ k } ) \] 

\[\text{ Let } :\]

\[ \vec{a} = \hat{ i }  + \hat{ j }  + 0 \hat{ k }  \]

\[ \vec{b} = 0 \hat{ i } + \hat{ j }  + \hat{ k }  \]

\[ \therefore \vec{a} \times \vec{b} = \begin{vmatrix}\hat{ i }  & \hat{ j }  & \hat{ k }  \\ 1 & 1 & 0 \\ 0 & 1 & 1\end{vmatrix}\]

\[ = \hat{ i  } - \hat{ j }  + \hat{ k } \]

\[ \Rightarrow \left| \vec{a} \times \vec{b} \right| = \sqrt{1 + 1 + 1}\]

\[ = \sqrt{3}\]

\[\text{ Unit vector perpendicular to } \vec{a} \text{ and } \vec{b} =\frac{\vec{a} \times \vec{b}}{\left| \vec{a} \times \vec{b} \right|} = \frac{\hat{ i }  - \hat{ j }  + \hat{ k } }{\sqrt{3}}\]

shaalaa.com
  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
पाठ 25: Vector or Cross Product - MCQ [पृष्ठ ३५]

APPEARS IN

आरडी शर्मा Mathematics [English] Class 12
पाठ 25 Vector or Cross Product
MCQ | Q 8 | पृष्ठ ३५

व्हिडिओ ट्यूटोरियलVIEW ALL [2]

संबंधित प्रश्‍न

Given that `veca.vecb = 0` and `veca xx vecb = 0` What can you conclude about the vectors `veca and vecb`?


If either `veca = vec0`  or `vecb = vec0`, then `veca xxvecb = vec0`. Is the converse true? Justify your answer with an example.


If θ is the angle between two vectors `hati - 2hatj + 3hatk and 3hati - 2hatj + hatk` find `sin theta`


If \[\vec{a} = 2 \hat{ i } + \hat{ k }  , \vec{b} = \hat { i }  + \hat{ j } + \hat{ k }  ,\]  find the magnitude of  \[\vec{a} \times \vec{b} .\]

 

 


Find the magnitude of \[\vec{a} = \left( 3 \hat{ k }  + 4 \hat{ j } \right) \times \left( \hat{ i }  + \hat{ j }  - \hat{ k }  \right) .\]

 

\[\text{ If }  \vec{ a } = 3 \hat{ i }- \hat{ j }  - 2 \hat{ k } \text{  and } \vec{b} = 2 \hat{ i }  + 3 \hat{ j } + \hat{ k }  , \text{ find }  \left( \vec{a} + 2 \vec{b} \right) \times \left( 2 \vec{a} - \vec{b} \right) .\]

 


Find the area of the parallelogram determined by the vector \[2 \hat{ i }  \text{ and }  3 \hat{ j } \] .

 


Find the area of the parallelogram determined by the vector \[2 \hat{ i } + \hat{ j } + 3 \hat{ k }  \text{ and }  \hat{ i }  - \hat{ j } \] .

 


Find the area of the parallelogram determined by the vector \[\hat{ i }  - 3 \hat{ j } + \hat{ k }  \text{ and }  \hat{ i }  + \hat{ j } + \hat{ k }  .\]

 


Find the area of the parallelogram whose diagonals are  \[2 \hat{ i }+ \hat{ k } \text{ and } \hat{ i } + \hat{ j } + \hat{ k } \]

 


Find the area of the parallelogram whose diagonals are \[2 \hat{ i }  + 3 \hat{ j } + 6 \hat{ k } \text{ and }  3 \hat{ i }  - 6 \hat{ j }  + 2 \hat{ k } \]

 


If abc are the lengths of sides, BCCA and AB of a triangle ABC, prove that \[\vec{BC} + \vec{CA} + \vec{AB} = \vec{0}\]  and deduce that \[\frac{a}{\sin A} = \frac{b}{\sin B} = \frac{c}{\sin C} .\]

 
 

if \[\vec{a} = \hat{ i }- 2\hat{ j }  + 3 \hat{ k }  , \text{ and }  \vec{b} = 2 \hat{ i }  + 3 \hat{ j }  - 5 \hat{ k }  ,\]  then find \[\vec{a} \times \vec{b} .\]  Verify th at \[\vec{a} \text{ and }  \vec{a} \times \vec{b}\] are perpendicular to each other.

 
 
 

 


Define  \[\vec{a} \times \vec{b}\] and prove that \[\left| \vec{a} \times \vec{b} \right| = \left( \vec{a} . \vec{b} \right)\] tan θ, where θ is the angle between \[\vec{a} \text{ and }  \vec{b}\] .

 
 

 


\[\text{ If }  \left| \vec{a} \right| = \sqrt{26}, \left| \vec{b} \right| = 7 \text{ and }  \left| \vec{a} \times \vec{b} \right| = 35, \text{ find }  \vec{a} . \vec{b} .\]

 


Using vectors find the area of the triangle with vertices, A (2, 3, 5), B (3, 5, 8) and C (2, 7, 8).


The two adjacent sides of a parallelogram are \[2 \hat{ i  } - 4 \hat{ j }  + 5 \hat{ k }  \text{ and }  \hat{ i } - 2 \hat{ j }  - 3\hat{ k }  .\]\  Find the unit vector parallel to one of its diagonals. Also, find its area. 

 
 

Using vectors, find the area of the triangle with vertice A(1, 1, 2), B(2, 3, 5) and C(1, 5, 5) .


Write the value of \[\hat{ i }  × \left( \hat{ j } + \hat{ k }  \right) + \hat{ j }   ×  \left( \hat{ k } + \hat{ i }  \right) + \hat{ k }  ×   \left( \hat{ i }  + \hat{ j }  \right) .\]

 

Write the expression for the area of the parallelogram having \[\vec{a} \text{ and } \vec{b}\] as its diagonals.

 
 

For any two vectors \[\vec{a}\] and \[\vec{b}\] , find \[\vec{a} . \left( \vec{b} \times \vec{a} \right) .\]

 
 
 
 

Write the value of \[\hat{ i }  \times \left(\hat{  j }  \times \hat{ k }  \right) .\]

 

If \[\vec{r} = x \hat{ i } + y \hat{ j }  + z \hat{ k }  ,\] then write the value of \[\left| \vec{r} \times \hat{ i }  \right|^2 .\]

 

 


If  \[\vec{c}\] is a unit vector perpendicular to the vectors \[\vec{a} \text{ and } \vec{b} ,\]  write another unit vector perpendicular to \[\vec{a} \text{ and }  \vec{b} .\]

 
 

 


Vectors  \[\vec{a} \text{ and }  \vec{b}\] \[\left| \vec{a} \right| = \sqrt{3}, \left| \vec{b} \right| = \frac{2}{3}\text{ and } \left( \vec{a} \times \vec{b} \right)\]  is a unit vector. Write the angle between \[\vec{a} \text{ and } \vec{b}\] .

 


Write the value of \[\left( \hat{ i }  \times \hat{ j }  \right) \cdot \hat{ k }  + \left( \hat{ j } + \hat{ k }  \right) \cdot \hat{ j } \]

 

Write the number of vectors of unit length perpendicular to both the vectors \[\vec{a} = 2 \hat{ i } + \hat{ j }  + 2 \hat{ k }  \text{ and }  \vec{b} = \hat{ j }  + \hat{ k } \] .

 

The unit vector perpendicular to the plane passing through points \[P\left( \hat{ i } - \hat{ j }  + 2 \hat{ k }  \right), Q\left( 2 \hat{ i } - \hat{ k } \right) \text{ and }  R\left( 2 \hat{ j }  + \hat{ k }  \right)\]  is 

 

If θ is the angle between the vectors \[2 \hat{ i }  - 2 \hat{ j}  + 4 \hat{ k }  \text{ and } 3 \hat{ i }  + \hat { j }  + 2 \hat{ k }  ,\]  then sin θ =

 

If θ is the angle between any two vectors `bara` and `barb` and `|bara · barb| = |bara xx barb|` then θ is equal to ______.


The number of vectors of unit length perpendicular to the vectors `vec"a" = 2hat"i" + hat"j" + 2hat"k"` and `vec"b" = hat"j" + hat"k"` is ______.


Let `veca` and `vecb` be two unit vectors and θ is the angle between them, Then `veca + vecb` is a unit vector if-


If `veca` and `vecb` are unit vectors inclined at an angle 30° to each other, then find the area of the parallelogram with `(veca + 3vecb)` and `(3veca + vecb)` as adjacent sides.


If `veca xx vecb = veca xx vecc` where `veca, vecb` and `vecc` are non-zero vectors, then prove that either `vecb = vecc` or `veca` and `(vecb - vecc)` are parallel.


If `veca` is a unit vector perpendicular to `vecb` and `(veca + 2vecb).(3veca - vecb) = -5`, find `|vecb|`.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×