AMU Engineering 2017 solved paper Solved Paper

According to the kinematic equation of motion, v2=u2±2gh
This equation is quadratic in terms of v and h.
Hence, the v - h graph would be a parabola.
As per the given condition, a ball is dropped vertically, implies that its initial velocity is downwards and therefore negative.
After collision, it reverses its original direction with smaller magnitude. Thus, the velocity is now upwards. Hence, only graph (b) satisfies these conditions.