 So, this question is teaching us what a doctor has prescribed a corrective lens of power this much. So, we know that power is reciprocal of focal length as the power is positive implies that the focal length is also positive and we know that the focal length of the con the vex-a lens is positive. So, the type of the lens is convex. This is we have extracted without even knowing what is given find the focal length of this lens. So, 1 upon here now as it is NCRT and CBSC in collaborated version beta. So, we will have to give a systematic answer and the answer for this is 520s hours or 200 by 3 centimeter is the focal length of the given lens. Why number 1? We have answered. Is this prescribed lens diverging and converging? So, as which is a converging lens answer done.