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

The point of coincidence on they-axis is Q(0,λ).The image of P(2,3) on the y-axis is P1(-2,3). P1, Q, and R are collinear. Therefore,Slope of P1 Q = Slope of P1R or     λ−30−(−2)=10−35−(−2)or     λ−3=2or     λ=5Therefore, the point Q is (0, 5).