question_answer

A light ray emerging from the point source placed at P (2, 3) is reflected at a point Q on the y-axis and then passes through the point R (5, 10). Coordinates of Q are

A) (0, 3)

B)  (0, 2)

C)  (0, 5)

D)  None of these

Correct Answer: C

Solution :

If \[{{P}_{1}}\] be the reflection of P in y-axis, then \[{{P}_{1}}\equiv (-2,3).\] Equation of line\[{{P}_{1}}R\]is \[(y-3)=\frac{10-3}{5+2}(x+2)\]\[\Rightarrow \]\[y=x+5\] It meets the y-axis at \[(0,5)\]\[\Rightarrow \]\[Q\equiv (0,5)\]