A bi-convex lens has radius of curvature of both the surfaces same as \( \frac{1}{6} \, \text{cm} \). If this lens is required to be replaced by another convex lens having different radii of curvatures on both sides \( (R_1 \neq R_2) \), without any change in lens power then possible combination of \( R_1 \) and \( R_2 \) is:
