Tag: transformation

Questions Related to transformation

If $B$ is reflection of $A(a,5)$ about line $4x-3y=0$, then area of triangle $ABC$ is equal to

  1. $\dfrac{253}{50}$

  2. $\dfrac{506}{25}$

  3. $\dfrac{253}{25}$

  4. $\dfrac{506}{50}$


Correct Option: A

Locus of the image of the point (2, 3) in the line (2x - 3y + 4) + k(x - 2y + 3) = 0, k $\in $ R, is a 

  1. straight line parallel to x-axis

  2. straight line parallel to y-axis

  3. Circle of radius $\sqrt { 2 } $

  4. circle of radius 3


Correct Option: A

The distance of the image of a point (or an object) from the line of symmetry (mirror) is  ----- as that of the point (object )from the line (mirror).

  1. same 

  2. double

  3. triple

  4. none


Correct Option: A
Explanation:
To make the above statement true, the word to be placed in the blank is : “same”
So, the true statement becomes :
The distance of the image of a point (or an object) from the line of symmetry (mirror) is same as that of the point (object) from the line (mirror).
Hence, option A is the correct answer.

The image of the point (-5,4) under a reflection across the y-axis is (5,4).

  1. True

  2. False

  3. Ambiguous

  4. Data insufficient


Correct Option: A

Image of $\left (1,2\right)\ w.r.t\left (-2,-1\right)$ is

  1. $\left (0,5\right)$

  2. $\left (-4,-3\right)$

  3. $\left (-4,-2\right)$

  4. $\left (-4,-5\right)$


Correct Option: D

If the line $\left (2\cos \theta+ 3\sin \theta\right)$ $x+(\left (3\cos \theta- 5\sin \theta\right)$ $y-\left (5\cos \theta- 2\sin \theta\right)=0$ passes through a fixed point $P$ for all values $\theta$ and $Q$ be the image of the point $P$ with the respect to the line $4x+6y-23=0$, then the distance of $Q$ from the origin is:

  1. $\dfrac {13}{5}$

  2. $\sqrt {5}$

  3. $5\sqrt {2}$

  4. $5$


Correct Option: A

The image of the point $A(1,2)$ by the line mirror  $y=x$ is the 
Point B and the image of B by the line mirror $y=0$ is the point $(a,\beta )then:$ 

  1. $a = -2,\beta = - 1$

  2. $a = 0,\beta = 0$

  3. $a = 2,\beta = - 1$

  4. none of these


Correct Option: A

A ray of light along $x + \sqrt {3y}  = \sqrt 3 $ gets reflected upon reaching $x - axis$ , then equation of the reflected ray is 

  1. $y = x + \sqrt 3 $

  2. $\sqrt 3 y = x - \sqrt 3 $

  3. $y = \sqrt 3 x - \sqrt 3 $

  4. $\sqrt 3 y = x - 1$


Correct Option: B
Explanation:
Mirror or reflecting surface/ boundary is $y = 0$ or $x-axis$.

Light Ray: $x + \sqrt3 y = \sqrt3$ or,
$\sqrt 3 y = \sqrt3 - x$.

Slope: $m = \dfrac{-1}{\sqrt3}$. Meets x axis at $A(\sqrt3, 0)$.

The reflected ray will have a slope$ = - m = \dfrac{1}{\sqrt3}$. Reason is that the angle of inclination with x axis becomes 180 - the angle of incident ray.

Also it passes through point $A$.

So the equation is: $y - 0 =\dfrac{ (x - \sqrt3)}{ \sqrt3}.$
Or, $\sqrt3 y - x + \sqrt3 = 0$.
Or, $\sqrt3 y=x-\sqrt3$

The line segment joining $A\left( {3,\,\,0} \right),\,\,B\left( {5,\,\,2} \right)$ is rotated about a point A in anticlockwise sense through an angle $\displaystyle{\pi  \over 4}$ and B move to C. If a point D be the reflection of C in y-axis, then D=

  1. $\left( { - 3,\,2\sqrt 2 } \right)$

  2. $\left( {3,\,2\sqrt 2 } \right)$

  3. $\left( {3,\, - 2\sqrt 2 } \right)$

  4. $\left( {3,\,8\sqrt 2 } \right)$


Correct Option: A
Explanation:
$A(3, 0)$ and $B(5, 2)$
Slope of AB$=\dfrac{2-0}{5-3}=1$
Then, if $\theta$, is the angle made by AB, with positive direction of x-axis, we have $\tan\theta =1$
$\Rightarrow \theta =45^o$
Given, AB is rotated by $45^o$ to AC
Now AB$=\sqrt{(3-5)^2+(0-2)^2}=2\sqrt{2}$
So, coordinate of pr w$(3, 2\sqrt{2})$
Hence reflection of c in y-axis is $(-3, 2\sqrt{2})$.

The reflection of the point $(2, -1, 3)$ in the plane $3x-2y-z=9$ is?

  1. $\left(\dfrac{26}{7}, \dfrac{15}{7}, \dfrac{17}{7}\right)$

  2. $\left(\dfrac{26}{7}, \dfrac{-15}{7}, \dfrac{17}{7}\right)$

  3. $\left(\dfrac{16}{7}, \dfrac{26}{7}, \dfrac{-17}{7}\right)$

  4. $\left(\dfrac{1}{6}, \dfrac{2}{3}, \dfrac{3}{4}\right)$


Correct Option: A